Note that Discworld has two common calendars. The Ankh-Morpork Calendar, which is based on the movement of celestial bodies, is 800 days long, but includes two full cycles of seasons. The Unseen Calendar, which is based on a single seasonal cycle of 400 days, sacrifices purity for practicality, and is thus far more popular. The Unseen Calendar will be used below.
In-universe, the Disc's general Anachronism Stew comes as a result of multiple Time Crash disasters - in particular the events that form the plot of Thief of Time - forcing the History Monks to reassemble the pieces. Those pieces don't always fit back together very neatly, so for example the Dysk Theatre (described in Wyrd Sisters as the city's first permanent structure devoted to theatrical performance) and the Opera House (described just five years later in Maskerade as having been a city landmark for decades already) are found on the same street, and the Patrician in The Colour of Magic fits the description of Lord Snapcase instead of Lord Vetinari despite Word of God confirming Vetinari had already come to power. For this reason, it's very difficult to establish a timeline that's both comprehensive and cohesive.
-2564
- Ankh-Morpork is founded on the Ankh River.
1
- The Unseen University is founded in Ankh-Morpork by Alberto Malich.
14
- After using an inverted Rite of Ashk Ente, Alberto Malich is summoned to Death's Domain. Rather than face his imminent demise, he finds work as Death's servant.
1196
- The Diet of Bugs is held in an Uberwaldean town of the same name. It establishes a balance of power between the Dwarfs, Werewolves, and Vampires that dominate the region. Note that Human and Troll populations were unrepresented.
1512
- The Murforte School for Gentlemen Assassins is opened. Within a few decades, it would gain Guild status.
1688
- The Ankh-Morpork Civil War occurs. The last king of the city, Lorenzo the Kind, is executed by "Stoneface" Vimes. Vimes would rule the city for several months before his death, after which the Vimes family was considered disgraced and the Patrician system keep into being.
1878
- Cohen the Barbarian is born. He would become one of the greatest barbarian heroes of all time.
1885
- Brutha becomes Cenobiarch of the Omnian Church. He begins a series of reforms. (Small Gods)
1947
- Lord Winder becomes Patrician of Ankh-Morpork.
1960
- The Glorious Revolution breaks out in Ankh-Morpork. Lord Winder is ousted via assassination, allowing politically important figures to arrange for the reign of Lord Snapcase. One of Snapcase's first actions is to purge the City Watch of the potentially dangerous "John Keel." Among the casualties was Reg Shoe, who died for a while before becoming a zombie. (Night Watch)
1964
- The infamous pub The Broken Drum burns down in a fire, which goes on to engulf much of Ankh-Morpork. Per Word of God, Lord Vetinari is already Patrician at this time.
- The Librarian of the Unseen University is transformed into an orangutan in a magical accident. He resisted any attempts to be returned to his human form. (The Color of Magic, The Light Fantastic)
1965
- Eskarina Smith becomes the first female student accepted at the Unseen University. (Equal Rites)
- Lord Mortimer becomes Duke of Sto Helit, after a short stint as Death's apprentice. Death attends a party celebrating the fifth anniversary of the current patrician's reign - suggesting the current patrician is Lord Snapcase, inaugurated in 1960. (Mort)
1967
- Granny Weatherwax sends the country of Lancre 15 years into the future. (Wyrd Sisters)
1970
- Internal evidence from Night Watch and The Fifth Elephant suggests this as the earliest possible date for Lord Vetinari's inauguration as Patrician.
1982
- King Verence II ascends to the throne in Lancre. (Wyrd Sisters)
1985
- Carrot Ironfoundersson joins the Ankh-Morpork Night Watch. Around this time, a dragon is summoned several times before temporarily establishing itself as king. (Guards! Guards!)
1986
- Edward d'Eath discovers that Carrot Ironfoundersson is the rightful heir to the throne. His mentor, Dr Cruces, attempts to assassinate Lord Vetinari. Detritus and Angua von Unerwald join the City Watch at this time. Samuel Vimes marries Lady Sybil Ramkin. (Men at Arms)
- Susan Sto Helit learns about her family's history with Death. (Soul Music)
- Cohen the Barbarian conquers the Agatean Empire. His Silver Horde, numbering eight men at their height, sucessfully defeats an army of 700,000. (Interesting Times)
1987
- The Golem Trust is established, with the goal of liberating the Golem race via buying each and every member from their owners. (Feet of Clay)
- Maskerade and Hogfather take place.
1988
- Ankh-Morpork and Klatch fight a brief war over the small island of Leshp, before the island sinks beneath the sea. Samuel Vimes becomes the Duke of Ankh. (Jingo)
- The Last Continent takes place.
- The Century of the Fruitbat ends.
1989
- The Century of the Anchovy begins.
- Vimes travels to Ubervald to observe the selection and enthronement of the new Low King, Rhys Rhysson. (The Fifth Elephant)
- The first Clacks commence operations.
- Carpe Jugulum takes place.
1990
- The Ankh-Morpork Times is founded. (The Truth)
- Magical lighting storm over Unseen University causes a serious rift in the time-space continuum. (The Thief of Time, Night Watch, The Wee Free Men)
- Young Sam Vimes is born.
1991
- Post Office reopens in Ankh-Morpork. (Monstrous Regiment, Going Postal, Thud!, A Hat Full of Sky)
1992
- Bank of Ankh-Morpork introduces paper currency. (Making Money, Unseen Academicals, Wintersmith)
1994
- I Shall Wear Midnight takes place.
1996
- Snuff takes place.
1997
- Raising Steam takes place.
1998
- The Shepherd's Crown takes place.
