Why is Saint Arthur of Glastonbury a saint?

Answer 1

Because was probably canonized by Pope Clemence VIII about 1600, but canonization was later stay secret by Vatican diplomacy which don't want conflict with British Kingdom and Anglican Church. Saint Arthur before died cursed Thomas Cromwell (died 7 months later) and king Henry VIII (died 7 years later and 3 last his words was "... Monks, Monks, Monks". Henry VIII died on unknown for medicine disease and his body stay covered by smelling bubbles. Some old medical sources named these disease "curse of St. Arthur" or "disease of Saint Arthur".

From these reason canonization decret (bulla) is stored probably in Secret Archive of Vatican, and no chance on finding name of Saint Arthur in anyone edition of Martyrologium Romanum or another "offical" list of Saints. Cardinal Henry Edward Manning when constructed at 1866 list of 360 British martyrs don't included St. Arthur (he was know that was canonized earlier). On his list was Richard Whiting OSB the last abbot of Glastonbury Abbey (now blessed) and two his blessed compans Roger James (vice-treasurer) and John Thorne (treasurer of Glastonbery Abbey). Some sources wrongly synonymized Blessed John Thorne (monk name Arthur was about 52 years when mordered) with Saint Arthur (about 24 years when mordered). Cult of Saint Arthur is opposed in recent time also from above reason. All Glastonbery martyrs are still treated in England as enemies of Tudors and Kingdom.