Odiham Castle is a ruined castle situated near Odiham in Hampshire, England. It is one of only three fortresses built by King John during his reign. Completed between 1207 and 1214, it fell to a French siege in 1216 but was later rebuilt. Used to host Parliament and, later, as a prison in the 13th and 14th centuries, by 1605 Odiham was described as a ruin. Its only visible remains today are part of the octagonal keep and outlying earthworks.Photograph: BabelStone