At the beginning of this period the boundaries of Alba contained only a small proportion of modern Scotland. Even when these lands were added to in the tenth and eleventh centuries, the term "Scotia" was applied in sources only to the region between the River Forth, the central Grampians and the River Spey and only began to be used to describe all of the lands under the authority of the Scottish crown from the second half of the twelfth century. By the late thirteenth century when the Treaty of York (1237) and Treaty of Perth (1266) had fixed the boundaries with the Kingdom of the Scots with England and Norway respectively, its borders were close to the modern boundaries. After this time both Berwick and the Isle of Man were lost to England, and Orkney and Shetland were gained from Norway in the fifteenth century.