Newcastle upon Tyne, or simply Newcastle, is a city and metropolitan borough in Tyne and Wear, England. It is located on the River Tyne's northern bank, opposite Gateshead to the south. It is the most populous settlement in the Tyneside conurbation and North East England. Newcastle developed around a Roman settlement called Pons Aelius, the settlement became known as Monkchester before taking on the name of a castle built in 1080 by William the Conqueror's eldest son, Robert Curthose.