Dublin (Irish: Baile Átha Cliath) is the capital and largest city of Ireland. Dublin is in the province of Leinster on Ireland’s east coast, at the mouth of the River Liffey. Founded as a Viking settlement, the Kingdom of Dublin became Ireland’s principal city following the Norman invasion. The city expanded rapidly from the 17th century and was briefly the second largest city in the British Empire before the Act of Union in 1800. Following the partition of Ireland in 1922, Dublin became the capital of the Irish Free State and later the Republic of Ireland.