Norse-Irish raiders from the Kingdom of Dublin sacked it. After that, the kingdom, now politically weakened, moved its capital to Govan. However, it never fully recovered, and in the 11th century it was annexed by the Kingdom of Alba. Medieval and early modern history In the 13th century, Glasgow, then still a small town, built its first bridge over the river Clyde. This was an important step in its ability to eventually grow into a city. The establishment, in the 15th century, of both the University of Glasgow and the Archdiocese of Glasgow, vastly increased the importance of the town within Scotland. From the early modern period onwards, the Clyde began to be used commercially as a trade route; trade between Glasgow and the rest of Europe became commonplace. In the centuries that followed, the Clyde became increasingly vital to both Scotland and Britain as a major trade route for exporting and importing resources. Course The Clyde is formed by the confluence of two streams, the Daer Water (the headwaters of which are dammed to form the Daer Reservoir) and the Potrail Water. The Southern Upland Way crosses both streams before they meet at Watermeetings () to form the River Clyde proper. At this point, the Clyde is only from Tweed's Well, the source of the River Tweed, and is about the same distance from Annanhead Hill, the source of the River Annan. From there, it meanders northeastward before turning to the west, where its flood plain serve as the site of many major roads in the area, and then reaches the town of Lanark. That is where the late 17th- and early 18th-century industrialists David Dale and Robert Owen built mills and the model settlement of New Lanark on the banks of the Clyde. The mills harnessed the power of the Falls of Clyde, the most spectacular of which is Cora Linn. A hydroelectric power station still generates electricity there today, although the mills have now become a museum and World Heritage Site. The river then makes its way northwest, past the towns of Wishaw to the east of it and Larkhall to the west of it. The river's surroundings here become increasingly suburban. Between the towns of Motherwell and Hamilton, the course of the river has been altered to create an artificial loch within Strathclyde Park. Part of the original course can still be seen: It lies between