History recalls, with its usual debatable certainty, that Ankh-Morpork was founded in – 2564UC. As new political entities tend to do, it immediately looked around for something to conquer. Much of the Discworld was available at this time, and for several hundred years Morporkia spread its power across most of the known world. The greatest burst of conquest occurred with the exploits of the great General Tacticus, whose dates are less certain, but probably ca. – 2000UC.
After Tacticus's campaigns, the Empire of Ankh-Morpork spread across nearly all the Unnamed Continent and far into Klatch. This accounts for the similarity of languages around the central continent, where versions of Morporkian are spoken as far away as Genua and places like Brindisi and Quirm speak derivations of the old Latatian. The central hinterland of Überwald and its neighbours was probably not continuously occupied, and retained the original tongues.
Toward the end of his career, when the rulers of Ankh-Morpork began to grow tired of receiving blood stained notes saying things like "...have conquered Betrek, Smale and Ushistan. Please send AM$20,000 back pay", the royal family of Genua had inbred themselves into extinction and so sent away to Ankh-Morpork requesting a candidate for the throne. The rulers, seeing their chance, immediately selected General Tacticus. Almost his first act in Genua was to assess the greatest military threat to Genua, and promptly declare war on Ankh-Morpork. This was the downfall of the over-extended empire and it began a long decline because of the same hero who had acquired so much of it. More than a thousand years later, King Tyrell appears to have fought Imperial battles in the Sto Plains and into the Ramtops, but Morporkia had shrunk considerably. By the time of the establishment of Unseen University (1 UC), power had shifted to wizards and the Empire had gone. Foreign adventures and particularly wars with Klatch continued as long as the monarchy, but Ankh-Morpork's territory declined to the small city-state which remains now.
The Emperor Carelinus, who wept because there were no new worlds to conquer, was presumably a Morporkian ruler and is described as having conquered the whole Disc, except for the Counterweight Continent and Fourecks.