Newcastle upon Tyne, commonly known as Newcastle, is a city and metropolitan borough in Tyne and Wear, North East England. Historically part of Northumberland, it is situated on the north bank of the River Tyne. The city grew up in the area that was the location of the Roman settlement called Pons Aelius, though it owes its name to the castle built in 1080, William the Conqueror's eldest son. The city grew as an important centre for the wool trade and it later became a major coal mining area. Newcastle's economy includes corporate headquarters, learning, digital technology, retail, tourism and cultural centres.