The Kings of Connacht were rulers of the cóiced (variously translated as portion, fifth, province) of Connacht, which lies west of the River Shannon, Ireland. However, the name only became applied to it in the early medieval era, being named after the Connachta. The old name for the province was Cóiced Ol nEchmacht (the fifth of the Ol nEchmacht). Ptolemy's map of c. 150 AD does in fact list a people called the Nagnatae as living in the west of Ireland. Some are of the opinion that Ptolemy's Map of Ireland may be based on cartography carried out as much as five hundred years before his time.