What is the oldest castle in Wales?

Wales' oldest lived in castle is Penhow Castle. Built by Sir William St Maur in the early 13th century

source Trivia

http://www.castles-of-britain.com/castle85.htm possibly whittington castle (actually now in shropshire, england) is amongst the oldest castles (approx 2 miles east of oswestry). it pre-dates 1221, which a number of castles seem to refer to this same year for stone build. though a 'castle' as been at this site since the early 9th century.