text: Between –, Gerard (), the Prior of the Holy Sepulchre, along with Patriarch Warmund of Jerusalem, wrote a significant letter to Diego Gelmírez, Archbishop of Santiago de Compostela citing crop failures and being threatened by their enemies; they requested food, money, and military aid in order to maintain the Kingdom of Jerusalem. Gerard consequently participated among others in the Council of Nablus, 16 January 1120. In it, Canons 20–21 deal with clerics. Canon 20 says a cleric should not be held guilty if he takes up arms in self-defense, but he cannot take up arms for any other reason nor can he act like a knight. This was an important concern for the crusader states; clerics were generally forbidden from participating in warfare in European law, but the crusaders needed all the manpower they could find and, only one year before, Antioch had been defended by the Latin patriarch of Antioch following the Battle of Ager Sanguinis, one of the calamities referred to in the introduction to the canons. Canon 21 says that a monk or canon regular who apostatizes should either return to his order or go into exile.
  In 1121, Pope Callixtus II issued a bull formally erecting the Canons Regular of the Holy Sepulchre with specific responsibilities to defend the Church Universal, protect the City of Jerusalem, guard the Basilica of the Holy Sepulchre and pilgrims, and fight in the defence of Christianity.