After the Romans withdrew from Caledonia, the village was part of the large Kingdom of Strathclyde, whose capital was at Dumbarton 15 mi (24 km) downstream. It merged in the 9th century with other regions to create the united Kingdom of Scotland.[1] The origins of Glasgow as an established city derive from its medieval position as Scotland's second largest bishopric. Glasgow increased in importance during the 10th and 11th centuries when this bishopric was reorganised by King David I of Scotland and John, Bishop of Glasgow.[2]