"PORCHESTER, (or Portchester), a parish in the hundred of Portsdown, county Hants, 2 miles S.E. of Fareham, its post town, and 7,-, from Portsmouth. It is a station on the London and South-Western railway. It is situated at the top of Portsmouth harbour under Portsdown Hill, and was the Roman Portus Magnus or Caer Peris of the Britons. A castle of great strength was erected on the old Roman works by the Saxons, who named it Portceastre, and which was rebuilt soon after the Norman conquest, and was held by Queen Margaret in the reign of Edward I. It subsequently came through the Nortons to Thistlethwayte of Southwick, and gives title of baron to the Earl of Carnarvon. "
[From The National Gazetteer of Great Britain and Ireland (1868) - transcribed by Colin Hinson ©2003]