1981 (Y1) AD = 100 MM = 56 TR = 55 RH = 53 M = 23 BW = 11 CW = 9 PW = 5 FGW = 3 HG = 2 H&R = 1 GW = 0
[Ginny Weasley] is born (JKR)
[Severus Snape] is hired by [Dumbledore] to teach [Potions] at [Hogwarts][Snape] had applied for the post of [Defence Against the Dark Arts], but [Dumbledore] refused.
In October of 1995 [[Y15]], [Snape] told [Umbridge] that he had been teaching at [Hogwarts] for 14 years, but unlike [McGonagall], he did not specify the month ([OP17]). He later says that he took up the post on [Voldemort]'s orders ([HBP2]), so it's almost certain he began teaching at the start of the school year.
The [Fidelius Charm] is cast to hide the [Potters], with [Peter Pettigrew] acting as Secret Keeper[Dumbledore] had offered to be secret keeper, but [James and Lily] had refused, planning to go with [Sirius Black] instead - but switching to [Pettigrew] at the last minute.
Fudge says that the [Fidelius Charm] was cast "barely a week" before [Voldemort] came after the [Potters].
Defeat of [Voldemort]; [James] and [Lily Potter] are killed[Voldemort] attempts to kill [Harry Potter] after murdering his parents, but the spell rebounds onto him.
[Voldemort], nearly dead and without physical form, retreats into the forests of [Albania] where he possess the bodies of various animals to survive for the next decade, waiting. [Hagrid], on [Dumbledore]'s orders, goes to [Godric's Hollow] to rescue baby [Harry] from the ruins of the house.
[Peter Pettigrew] fakes his own death, killing twelve Muggles in the process[Sirius Black] is arrested and at some point in the next few weeks is sent to [Azkaban] without a trial. He is 22 years old.
It's about 90% certain this happened on November 1, but it's also possible it was November 2.
[Hagrid] delivers baby [Harry] to [Dumbledore][Dumbledore] is waiting in [Privet Drive] to leave the baby with the [Dursleys].
but there are [twenty-four hours missing] from the chronology of events of these two days...
[Sirius Black] is framed for the murders of [Peter Pettigrew] and twelve Muggles on November 1, 1981He is sent by [Bartemius Crouch Sr.] to [Azkaban] without a trial.
This almost certainly happened immediately following [Sirius]'s capture on November 1, but we have no way of knowing for sure.
[Bellatrix], [Rodolphus], and [Rabastan] Lestrange, along with [Bartemius Crouch Jr.], are arrestedThey are charged with using the [Cruciatus Curse] on [Frank and Alice Longbottom] in an attempt to discover the whereabouts of [Voldemort]; all of the accused are convicted and sent to [Azkaban]. [Frank and Alice Longbottom] are committed to [St. Mungo's Hospital for Magical Maladies and Injuries], driven permanently insane from the [Cruciatus Curse].
We know that this happened shortly after [Voldemort]'s downfall, as [Dumbledore] says it was "just when everyone thought they were safe." They likely happened sometime between November 1981 [[Y1]] and very early 1982 [[Y2]].
after 1981 (Y1)