Several of the regional kings were at various points independent of their provincial over-king and indeed rivalled them in power and territory. ' was originally part of Connacht but much of it lay in what is today Ulster. It later split into East and West Bréifne. ' (Oriel) and ' (also known as the Northern Uí Néill, in contrast to the Southern Uí Néill who ruled '; ' or ', both meaning "the North"; '; and Tyrone/') were nominally part of '. ' (Ossory) was originally part of ', but lay between ' and ' and was controlled by both at various points. Dál Riata was also an Irish (sub-)kingdom, which mostly lay in modern Argyll and Bute in Scotland but originated in and initially extended into north-eastern Ireland and was (nominally) subject to '. In the 12th century Munster was split into two smaller over-kingdoms: ' (Desmond, literally South Munster) and ' (Thomond, literally North Munster).