He was one of the feudal
barons who became a target for the anger of
King John of England, whose forces attacked
Oswestry town and burned it in 1216. John FitzAlan was close to
Llywelyn ap Iorwerth until 1217. He was also a representative of the Crown in a dispute between
King Henry III of England and the
Welsh leader,
Llywelyn the Great in 1226. In the same year he mediated between a neighbour,
William Pantulf (died 1233), Lord of
Wem in
Shropshire and
Madog ap Gruffydd (died 1236), Lord of
Powys and a cousin to
Llywelyn ap Iorwerth. In 1233/4 during the conflict between King Henry III, the
Earl Marshal, and Llywelyn the Great, John FitzAlan sided firmly with the Crown and Oswestry was again attacked, this time by Welsh forces. ==Marriage and issue==