1776

- Barnabus Stinson is asked by George Washington and Benjamin Franklin to write a collection of rules regarding the way a bro should behave after an incident where Franklin accused Washington of codpiece blocking him. Barnabus calls this list of rules "The Bro Code".  [According to Barney in 317 The Goat. Contradicted in 904 The Broken Code when Barney says that 'Broses' brought the bro code from the heavens]

- Christopher Brolumbus journeys to the new world to see Pocahontas and brings with him the Bro Code. [According to Barney in  904 The Broken Code. Of course this directly contradicts the previous entry which says the Bro Code was invented in 1776. In reality Christopher Columbus discovered America in 1492 and Pocahontas died in 1617 ]

1807 

-  Barney's ancestor's carriage accidtenally hits a gypsy woman and she curses the Stinsons with horniness and for the next two hundred years the male members of the family are affected by the curse. [According to Barney in 902 Coming Back]

1843

- At the Farhampton Inn in room 13 notorius murderer Captain Blazing Dearduff The Hooker, freezes to death after he gets his hook stuck in the wall. He continues to haunt the room to this day. [According to The True And Real Ghost Stories Of The Supernatural TV show the gang watch in 907 No Questions Asked. Most people believe he's actually just a male prostitute who died of syphillis in 1848]

1941

- At Columbia University President Franklin D. Roosevelt commissions Barney's ancestor Dr. Barnett Stinsonheimer create a miracle hangover cure in a secret project called the "Too Many Manhattans Project". The project is a success and Dr. Stinsonheimer wins the Bro-bel prize. [According to Barney in 916 Rally]

1951

​- Marshall's father, Marvin Eriksen Sr is born. [According to his tombstone in 714 Tailgate]​

1974

- James Stinson, Barneys older brother is born. [According to 602 Cleaning House he's two years older than Barney]​​

1976

- Ted's parents get married. [30 years before 203 Brunch]​

- Somewhere between October 23rd-November 22nd. Barney Stinson is born. ​[See note *2 below]

1978​

- March. ​Lily Aldrin is born. Her dad Mickey is the one who takes care of her mostly when she's young, as her mum goes back to work. [She's 32 in 518 Say Cheese, March based on the month that episode aired. Some sites list her birthday as being March 22nd, but this is based solely on the fact that this episode aired on this exact day. As this was not specifically stated in the episode and there's no precedent to say airdates match actual show events I'm just going to leave it as being March. In the words of Marshall: "Lawyered".].​​ [In 803 Nannies Lily's dad reveals he was her main caregiver until she went to pre-school]
- April 25th. Theodore "Ted" Evelyn Mosby is born in Shaker Heights, Ohio. [First established in 317 The Goat]​

- Between April and November. Marshall Eriksen is born. [He says he's 29 in The Yips, set in 2007. As that episode is set in November it's very likely he's already had his birthday that year.]

1979

- Barney's mother Loretta Stinson leaves Barney alone for three weeks to go on tour with Grand Funk Railroad and she spends the time "getting passed around like a bong".  [Stated as happening when Barney was three years in 414 The Possimple]

1980

- July 23rd. In Canada Robin is born. Her father is disappointed she isn't a boy, but names her Robin in Charles Scherbatsky Junior anyway. [Exact birthday revealed In 503 Robin 101. Her birthday is mentioned as being on July 23rd and that she's 29. This episode was set in October 2009, meaning Robin has already turned 29 that year and was born in 1980]

1981

- July 23rd. A five year old Barney uses a rib from a dinosaur to knock down a giant model of a blue whale at the Museum of Natural History. The story becomes legendary among museum staff. [Exact date given in 608 Natural History]

- Unknown Date. Barneys grandfather dies and he attends the funeral. [Barney says in 111 The Limo he went to his grandfathers funeral when he was five]
1982 

- Barney and James ask their mother why they look different. They are told it's because when she was pregnant with James she only ate chocolate ice cream while with Barney she only ate vanilla. [210 Single Stamina]​

- Nora, later Barney's girlfriend is born. [she's 29 in 705 Field Trip]​

- Lily starts pre-school. On her first day her dad, who has been her main caregiver up this point while her mum worked, struggles with what to do with himself without her during the day, eventually decides to go gamble. This would be the start of his gambling addiction and the deterioration of his relationship with Lily. [Presuming Lily started pre-school at the usual age of four, 803 Nannies]
1983 ​

- The last time Barney sees his "Uncle Jerry" (in reality his dad) [According to 621 Hopeless. This directly conflicts with Natural History where Barney says he last saw his dad in 1981]​
1984

- September. Ted's future wife, Tracy McConnell is born. [She turned 21 in 2005 according to 916 How Your Mother Met Me]

- Barney and James ask their mother why they look different  and they are told it's just "one of those things" [210 Single Stamina]​

- After eight-year-old Barney vomits at the planetarium on a school field trip no-one attends his birthday party. His mum writes a letter, supposedly from the Postmaster General saying they lost all of his inviations, and gives it to Barney so he won't feel bad. [602 Cleaning House]

- Seven year old Lily goes to the hospital to have tonsil surgery. Her father Mickey scares the crap out of her. He also mistakenly tells her that he and her mum are getting divorced [723 The Magicians Code]​

1985

- February 21st. Singer Weird Al Yankovic gets a letter from an eight year old Ted suggesting songs he could do. Al hates most of the list but loves Teds suggestion to do "Like A Surgeon" and immediately rushes off to record it. When he releases it a couple of months later Ted is the only one who knows the truth about where he got the idea for it. [707 Noretta. In reality Weird Al Yankovic really did record Like A Surgeon on this day!]​

- April. Lily's 7th birthday. Her dad forgets its her birthday and takes her to the racetrack so he can gamble. [803 Nannies. Lily's birthday has been established as occuring in April and in the episode she stated her birthday was happening on that day. The end credits say that Lily was 7 at the time this happened.]

- After June 7th. Shortly after her parents separate eight year old Lily goes to the movies to see The Goonies. It becomes one of her favourites and even over twenty years later she'll still be able to recite every line from it. [According to 518 Say Cheese Lily saw the movie in the theatre, and in real life The Goonies was released on June 7th 1985 so she must of seen it some time after that date.]

-  Seven year old Ted visits Geauga Lake amusement park and gets a wild west photo taken of himself and his best friend (a balloon). He later would lose the balloon after he lets go of it. This teaches him to hold on tightly to things he loves. [908 The Lighthouse, 917 Sunrise]

1986  

- Barney and James ask their mother why they look different and they are told to "stop being racist". [210 Single Stamina]​

- Six year old Robin's dog, Sir Scratchewan, becomes sick and dies. In order to prevent Robin from being upset about this her parents tell her he underwent an experimental procedure and as a result turns into a turtle. It takes Robin longer than she'd care to admit to realise what happened [The end credits of 320 Miracles state that Robin was six when this happened]

-  Eight year old Marshall is dumped by Nicole Barsamian, who proceeds to show him how much better she's doing without him. [416 Sorry Bro, stated in the credits that Marshall was eight when this happened]

1987

- Nine year old Ted gets trapped underneath a rock at a shopping mall. [strongly implied to have happened in 209 Slap Bet]

1988

- Ten year old Marshall stops wetting his bed. [he says he wet his bed until he was 10 in 209 Slap Bet]

- Ten year old Marshall reads a book called Life Among The Gorillias and dreams of being a anthropologist but after a lecture by the books author, during which she tells him all the gorillas will be dead by the time he has the chance to do it, this inspires him to become an environmental lawyer. [117 Life Among The Gorillas]

- Twelve year old Barney is teased by a bully named Matthew Panning, who says that he has slept with a hundred women. This results in Barney declaring he would sleep with two hundred women, which he finally accomplishes twenty one years later. [422 Right Place, Right Time. The end credits confirm Barney is twelve when this happens]

- Lily's dad Mickey misses her ballet recital as he's working on his new board game, Tijuana Slumlord. [509 Slapsgiving 2: Revenge Of The Slap]

- Ten-year old Marshall rides his bike down a ladder and is knocked unconscious. He's in a coma for "under a week".[According to the end credits of 520 Home Wreckers he was ten when this happened.]

- Ten-year old Marshall steals the family car and drives it down the wrong side of the freeway. [According to the end credits of 520 Home Wreckers he was ten when this happened. It's unknown which of this, or the above events happened first.]

1990 ​

- Marshall wins camper of the year at Lutheran Hills Day Camp in Brunswick, Minnesota. [Briefly shown on screen in 414 The Possimple as part of Marshall's resume]

1991

- Summer. At summer camp 12-year old Marshall starts smoking. [511 Last Cigarette Ever]​

1992 ​

- 9th grader Ted saves a 4th grade boy named Steve Biel from some bullies, years later Steve would use the name "Ted Mosby" as his alias as a porn star in honour of his savior [306 I'm Not That Guy], ​

- Lily farts really loudly in class and blames it on another kid, Michael Sasser. The kid gets the nickname Gasser from the incident and later has to move schools because of the teasing [406 Happily Ever After]​

1993 ​

- The last time Ted vomits until 2005. ["Vomit Free Since '93" according to The Pineapple Incident and its revealed he threw up in September 2005 in 115 Game Night]

- 15 year old Marshall writes a list for himself to read when he turns 30 of the goals he wishes to achieve including driving a "kick ass" Camaro or the A Team van, his rat tail hangs down to his knees, he can still slam dunk, has legally changed his name to Vanilla Thunder, a description of his perfect wife (blonde, six feet tall, an awesome rack and caters to his every need), he's still rocking the overalls and most importantly is saving the world. [510 The Window]

- The owner of a mall magic store, Mr. Flanagan, teaches a young Barney about magic and the magicians code. He doesn't realise of course that he's also banging his mum and he wouldn't figure it out until 2012. [I said a bang bang bangity bang...] [724 The Magicians Code Part 2]

- Robin's dad takes her on a wolf hunt and she nearly dies of malnutrition. [A year before 1994. 823 Something Old]

- An unscrambled Spice channel glitch gives Marshall one of his best by yourself times. [915 Unpause]

1994

- In St Cloud, Minnesota 16 year old Marshall is on the hook of Lisa Walker whom he's in love with but she has no real interest in him. One night he goes to declare his love for her by singing her a song but while waiting for her to get home [516 Hooked]

- July 23rd. On her 14th birthday Robins father, Robin Scherbatsky Sr drops her into a remote forest with a knife where she must survive on her own for a three days. [Robin's birthday has been established as being July 23rd. 706 Mystery vs. History]​​

- Robin's dad takes her to visit New York for the first time. She decides to bury her grandmothers locket in central park, so that when she gets married that she'll come back and find it and use it as her something old. [823 Something Old]

- Robin's peewee hockey team wins the Squamish invitational. While celebrating at her house Robin's dad catches her making out with a team mate and finally realises she's not a boy. Eventually she decides to move in with her mom.[She's fourteen according to 406 Happily Ever After]

- 16 year old Lily meets and begins dating a guy named Jeff, who she renames Scooter. Together the two of them engage in badass behaviour, including underage drinking and Lily slaps a police officer. [According to Lily in 808 Twelve Horny Women, though it does seem likely that Lily's story is true].

- Ted attends the Shaker Heights Renaissance Fair and gets a photo of him in the stocks. [808 Twelve Horny Women]

1995 

- July 4th. Lily "The Belly" Aldrin wins a hot dog eating contest by eating 29 hot dogs in eight minutes. [414 The Possimple]​

- Ted loses his virginity to Molly Mackenzie. She leaves him right afterwards to go light some firecrackers in the woods. She asks Ted if she can borrow twenty bucks, promising to pay him back. But. She. Doesn't.  [212 First Time In New York]​

- After a series of tests Marshall is given a Pontiac Fiero by his brothers, but only after they pull one final prank on him first. [A literal burn!] [217 Arrivederci, Fiero]​

- Marshall is named the Nicollet County Slam Dunk champion in Minnesota after a three day dunking championship. [414 The Possimple]​

1996 

- Marshall is a finalist in the National Environment Esssay competition and is one of ten high school seniors who has their essay published in the National Journal of Environmental Sciences. [Briefly shown on screen in 414 The Possimple as part of Marshall's resume]

- Lily attends her high school prom with her boyfriend Scooter. They break up when Lily decides the two of them want different things.  [120 Best Prom Ever]

- 22nd June. In Brooklyn, New York Lily graduates from high school but her dad misses her graduation. He also steals all her babysiting money and uses it to develop his boardgame "Who Stole The Babysitting Money?", an irony that goes right over his head. [713 Tailgate]

- Robin has a brief career as pop star Robin Sparkles releasing two singles 'Lets Go To The Mall' and 'Sandcastles In The Sand'. She spends the year touring malls promoting it. During the brief Canadian summer she dates Simon. [209 Slap Bet, 316 Sandcastles in the Sand]. She later loses her virginity [212 First Time In New York]​​

- At high school Marshall ties with Egdud Furhaki for Most Outgoing. [818 Weekend At Barney's]

- Late. Ted, Marshall & Lily start College. [305 How I Met Everyone Else]

- Marshall meets and begins dating Lily*1 [305 How I Met Everyone Else] 

- After their third date Marshall already knows he loves Lily, but is unsure whether he should stay with her or not as he's so young. Ted convinces him to stay with her. [807 The Stamp Tramp]

- Lily and Marshall lose their virginites to each other. [212 First Time in New York]​

- Ted breaks up with Karen after she cheats on him (It's not clear which of the many times they broke up this was but is not the time they broke up on a plane to Paris) and writes himself a letter about why he had broken up with her in case he ever wanted to get back together with her. Though he would anyway despite the fact Karen is clearly a douche. [521 Twin Beds]​

- November 14th. Marshall and Lily play one hackysack game with a guy named Daryl LaCoutre but afterwards he becomes obsessed with them and calls them hackmigos and even fifteen years later he still won't leave them alone. [811 The Final Page Part One]

- November 24th. Robin Sparkles is schedule to perform at the Canadian football league championship, the 84th Grey Cup game. Shocking everyone though she emerges as her much darker alter ego Robin Daggers and sings "P.S. I Love You", a song she wrote about her obsession with Paul Shaffer. It is a such a shocking event that every Canadian will remember where they were, and what donut they were eating at the time it happens. [In real life the 84th Grey Cup match really was played on this day. 815 P.S. I Love You]

- December. The 100k Fiasco/Fieroasco where Ted & Marshall got lost on the way home for Christmas break and need to cuddle together to stay warm. It's during this trip that the two become friends. [217 Arrivederci, Fiero]​​

1997 ​

- February 14th. On their first Valentine's Day as a couple Lily and Marshall decide to watch Sleepless in Seattle but Marshall's brothers taped over it with Predator. Unfazed they decide to just watch Predator, and every year after that they always watch Predator on Valentine's Day. [According to 616 Desperation Day this tradition started on their first Valentine's Day as a couple].

- Marshall, Lily & Ted dress up as salt & pepper and cumin. [704 Stinson Missile Crisis]​

- Ted meets Maggie Wilks at college, the ultimate girl next door, and falls in love with her, however she's dating someone else. [In 510 The Window, set in 2009, Ted says he's been in love with her for 12 years and it's stated he's had feelings for her since they met]

- Ted gives his mother a plush turtle with a recording of his voice saying "I wuv you mommy" as a present. [Ted was 19 according to 915 Unpause]
1998

- February 5th. Lily paints Marshall nude. Karen lingers. [416 Sorry Bro]​

- March. Sophmore year of college, Lily arrives back from her trip to Fort Lauderdale with a 6pack and Marshall greets her at the airport. It starts a tradition. [413 Three Days of Snow]
- From this year until he graduates from college Ted is a program director for the colleges radio station, most notably appearing on air as "Doctor X". [414 The Possimple, exact position and years shown briefly on screen as part of Ted's resume]

- Summer. Ted works as a supervising lifeguard in Columbus, Ohio as a summer job. [414 The Possimple]​

- Barney and his girlfriend Shannon break-up, after she leaves him for a business man named Greg, devastating him.  [Eight years ago from 2006, 115 Game Night]​

- Barney gets a job doing P.L.E.A.S.E. (Provide Legal Excuplation And Sign Everything) in order to get revenge on Greg, who doesn't even recognise him. It would take fifteen years before the revenge would finally come. [915 Unpause]

- Ted breaks up with Angie after Lily interfers in their relationship. [417 The Front Porch]​

- Ted goes to an N'Sync concert at the Agora Theater in Cleveland. He's in the front row and catches JC Chasez's shirt. [In real life N'Sync really did play in Cleveland in July 1998, but not at the Agora Theater, though its possible Ted was mistaken. 618 A Change of Heart]​

- Marshall, Lily & Ted dress up as Lady & The Tramp and their bowl of spaghetti. [704 Stinson Missile Crisis]​

- Lily robs a liquor store by putting bottles under her dress and claiming she's pregnant. She's picked up by Marshall and Ted in the fiero and they make a speedy getaway. [724 The Magicians Code Part 2]

1999

- January 17th. The Minnesota Vikings lose their NFC championship game to Atlanta after placekicker Gary Anderson misses a field goal. It is a source of much disappointment about Minnesotans, Marshall's father sheds a tear and tells him that a part of him "just died" because of it. [411 Little Minnesota]​

- Summer. Ted works as a Summer Associate for Gradmore, Jellinek & Ross in Boston. [Shown onscreen as Part of Teds resume in 414 The Possimple]​​​​

- ​July. Marshall arrives back from his trip to Amsterdam and manages to get through customs with some weed due t​​o a miraculous shift change. [320 Miracles]​

​- Barney loses his virginity to Rhonda 'The Manmaker' French . [He says he was 23 in 212 First Time in New York]
- Ted & Marshall, high on Tantrum, drive to Chicago to go to Gazola's Pizza. [505 Duel Citizenship]​​

- Marshall goes to visit Lily in Paris with Ted & Karen but things don't go as planned when Karen reveals to Ted that she cheated on him with a professor on the way there. [518 Say Cheese]

2000​

- While studying for an Econ final at college Marshall and Ted decide to watch the Star Wars trilogy and make a pact to watch the trilogy ever three years. On the test they both get zeros. [720 Trilogy Time]​

- Marshall, Ted and Lily graduate from college. [20 years before 2020. 305 How I Met Everyone Else]​

- Marshall and Ted move in to their apartment and put up swords. [Five years before 108 The Duel]​

- Marshall eats the best burger ever. Years later he would try to find the place with much difficulty. [402 Best Burger In New York] ​

- Ted's future girlfriend, Stella Zinman's daughter; Lucy is born. [She's 8 in 313 Ten Sessions]​

- Ted's college crush, Maggie Wilks, moves to New York and breaks up with her college boyfriend. Ted respectfully waits a week before he asks her out, not wanting to be the rebound guy, but by the time he goes to ask her out she's already met someone else, someone she dates for two years [9 years before 510 The Window. In the episode it says following this she dates guys for 2 years, then 3 years, then 4 years = nine years.]

- Marshall, Lily & Ted dress up as Lewis & Clark and their canoe. [Probably for Halloween, 704 Stinson Missile Crisis]​
2001

- October 31st. Ted meets the Slutty Pumpkin, Marshall and Lily dress up as Sonny & Cher.  [It's unknown if they know Barney at this time, 106 Slutty Pumpkin]​

- Barney meets Ted, Marshall and Lily. [305 How I Met Everyone Else]​

- Lily attends her one and only karate class, after she's beaten up by a 7-year-old. Nine years later she would return to the dojo for a rematch with same kid, who's now sixteeen. [According to the end credits of 603 Unfinished the kid is 7 and 16 years old respectively]
2002

​- May. Ted dates a "weird sci-fi girl" who proposes to him after 2 months. Lily breaks them up at the Star Wars Episode II: Attack of the Clones premiere. [In real life this film came out in May 2002 417 The Front Porch]
- June. Marshall arrives back from Minnesota with Minnecider for Lily, continuing their tradition. [413 Three Days of Snow]​

- October. Ted dates Natalie. He breaks up with her on her birthday via a voicemail, which her friends and family hear as they wait for her to arrive home for a surprise party Ted didn't know was happening. [Three years before 104 Return of the Shirt. October based on the fact that like in this episode, which is set in October, Ted also breaks up with her on her birthday.]​

- Barney's mom becomes critically ill and so to grant her last request Barney pretends to have a wife, and later a son. When his mom later gets miraculously better he realises he now he has to keep up the charade. ["About seven years" before 415 The Stinsons]

- After a wrestling match Canadian celebrity wrestler, The Frozen Snowshoe, invites Robin back to his apartment to look at his collection of Harveys trays. She's asked to leave when she offers to perform an Old King Clancy on him. [418 Old King Clancy]​

- Ted goes on a blind date with a girl named Jen and doesn't call her back. Seven years later he goes out with her again. [502 Double Date]​

- Ted's college crush, Maggie Wilks, breaks up with her boyfriend. Ted waits a week before he asks her out but again he's too late and she dates her new boyfriend for the next three years. [510 The Window. 7 years before 2009 based on Ted's calculations of how long she's dated each boyfriend].

- Lily and Marshall make the first of their long term bets when Lily bets Marshall Ted will break his leg while skiing. He breaks his arms but they decide to make it a ongoing game. [717 No Pressure]​

- December 31st. Ted, Marshall and Lily spend the night doing karaoke, including dressing up and performing as Destiny's Child, with Ted as Beyonce. [823 Something Old]

2003

- September. Tracy's boyfriend Max gets her an exact replica of Pee-Wee Herman's bike from Pee-Wee's Big Adventure. [Two years before September 2005. 916 How Your Mother Me Me]

- Ted's future girlfriend Stella Zinman and her boyfriend Tony break up. [Mentioned as being five years ago in 405 Shelter Island]

- The last time Stella has sex until with Ted in 2008. [It is unclear whether or not this was Tony but most likely 318 Rebound Bro]​

- Trilogy Time 2003. At this point Marshall hasn't managed to get into law school, and is the manager of a Structure mens clothing store. [720 Trilogy Time]​
2004​

- September. Tracy's boyfriend Max gets her a one-man band suit, inlcuding knee cymbals. [A year before September 2005. 916 How Your Mother Me Me]

- October 31st. Marshall dresses up as Tarzan for Halloween and gets frostbite. ["Tarzan nipple pinchy" 106 Slutty Pumpkin]

- November 26th. Ted walks to the apartment to find Lily painting some acrobats. [409 The Naked Man]

- Teds parents separate. [2 years before 203 Brunch]​

- Marshall is accepted into Columbia law school. To celebrate he eats a eight pound block of fudge in 12 minutes which earns him the nickname "Big Fudge".  [Marshalls 2nd year of law school was in 2005 according to 101 The Pilot. The origins of Big Fudge were revealed in 918 Rally]​

- Lily and Marshall make a sex tape and although Lily is worried Barney will see it Marshall bets Lily that Barney he won't. [717 No Pressure]​

*1 - In 114 Zip Zip Zip (set in February 2006) Marshall and Lily celebrate their nine year anniversary. This appears to be an error on the writers part as Lily and Marshall would be celebrating their tenth anniversary that year, and their anniversary should be later in the year, as they met as Marshall was just starting college. One possibility is that for some reason they had to delay their anniversary celebrations until this point.

*2 - There is some issues dating Barney's birthday. What year was Barney born? - According to 519 Zoo or False he was born 7 years after 1969, meaning his birthdate would be 1976,. However in 608 Natural History Barney says he was six when he knocked the blue whale down in the Natural History museum. This inconsistent as he'd be five that year. It is possible that Barney simply made a mistake when he said he was six when this happened. For the purposes of this timeline (as without a birth year dating other events becomes difficult), I'm using 1976 as his birth year. What day/month was Barney Born? Barney doesn't celebrate a birthday during the series, and his birthday is never stated, so all we ahve to go on is what was mentioned in one episode - according 716 The Drunk Train Barney's a scorpio so his birthday is somewhere between October 23rd and November 22nd.