Hadrian's Wall was built by the Romans across the width of Great Britain, from Solway Firth in the West to the River Tyne in the East, to separate Romans from the "barbarians" to the north. By this period, the Roman Empire had ceased to expand, and Emperor Hadrian who had come into power in 117 A.D., was more concered with protecting his borders. The wall was built upon his orders when he visited Britain in 122 A.D. Hadrian's Wall was meant to define the frontier physically and encourage economic stability by providing a buffer between the "civilized" south and the unruly northern tribes. The wall served as the northern border of the Empire in Britain for most of the Roman Empire's reign. The gates through the wall also served as customs posts, allowing trade to be taxed. Originally 15 feet high with 6 foot battlements, large portions of the wall still exist and are one of the most popular tourist attractions in Northern England. Today, it is often referred to as the Roman Wall.