An important religious guild, the Confraternity de Salve Regina, was in existence by 1343, having been founded by the "better sort of the Parish of St Magnus" to sing the anthem 'Salve Regina' every evening. The Guild certificates of 1388/89 (12 Richard II) record that the Confraternity of Salve Regina and the guild of St Thomas the Martyr in the chapel on the bridge, whose members belonged to St Magnus parish, had determined to become one, to have the anthem of St Thomas after the Salve Regina and to devote their united resources to restoring and enlarging the church of St Magnus. An Act of Parliament of 1437 provided that all incorporated fraternities and companies should register their charters and have their ordinances approved by the civic authorities. Fear of enquiry into their privileges may have led established fraternities to seek a firm foundation for their rights. The letters patent of the fraternity of St Mary and St Thomas the Martyr of Salve Regina in St Magnus dated 26 May 1448 mention that the fraternity had petitioned for a charter on the grounds that the society was not duly founded.