biblical commentator and theologian. Born c.1080 or slightly later, he taught at Paris before becoming Bp. of Poitiers in 1142. He wrote commentaries on the Psalter and Pauline Epistles, but he is chiefly remembered for that on the theological opuscula of Boethius. The language used in this work on how to reconcile the statements ‘God is one’ and ‘God is three’ aroused opposition, and Gilbert was summoned to appear before the Council of Reims in 1148. Despite pressure from St Bernard, there was no formal condemnation. His followers were known as the Porretani.