John of England is a reference to King John I, who ruled England from 1199 to 1216. He was the youngest son of Henry II and Eleanor of Aquitaine and was known for signing the Magna Carta in 1215. The crossword solutions LOO and ELTON refer to two of his castles. LOO is a reference to Ludlow Castle, which was built in the 11th century and served as a royal residence for John and his court. Elton is a reference to Eltham Palace, which was built in the 14th century and served as a royal residence for John and his court.