Ptolemy's "Geographia", written in the 2nd century, places the "Uoluntii" or "Voluntii" in the southeast of what is now Ulster, somewhere south of the River Lagan and north of the River Boyne. To their north were the Darini and to their south were the Eblani. Muirchú's "Life of Patrick", written in the 7th century, also says that the territory of the "Ulothi" lay between the Lagan and the Boyne. In the Ulster Cycle of Irish mythology—which survives in texts from the 8th century onward—the pre-historic Ulaid are said to dominate the whole north of Ireland, their southern border stretching from the River Boyne in the east to the River Drowes in the west, with their capital at Emain Macha (Navan Fort) near present-day Armagh, County Armagh. According to legend, around 331 AD the Three Collas invaded Ulaid, destroyed its ancient capital Emain Macha, and restricted Ulaid to the eastern part of its territory: east of the Lower Bann and Newry River. It is said that the territory the Three Collas conquered became the kingdom of Airgíalla. Another tradition that survived until the 11th century dated the fall of Emain Macha to 450 AD—within the time of Saint Patrick—which may explain why he chose Armagh, near Emain Macha, as the site of his episcopacy, as it would then still be under Ulaid control. It may also explain why he was buried in eastern Ulster in the restricted territory of the Ulaid rather than at Armagh, as it had by then come under Airgíallan control. It is likely that the Airgíalla were not settlers in Ulaid territory, but indigenous tribes; most of whom were vassals of the Ulaid before casting off Ulaid overlordship and becoming independent. It has been suggested that the Airthir—in whose lands lay Emain Macha—were originally an Ulaid tribe before becoming one of the Airgíalla.