The largest guild in Strasbourg, the "Gärtner" or Gardeners, appointed him as the pastor of St Aurelia's Church on 24 August 1523. A month later the council accepted his application for citizenship. In Strasbourg, Bucer joined a team of notable reformers: Zell, who took the role of the preacher to the masses; Wolfgang Capito, the most influential theologian in the city; and Caspar Hedio, the cathedral preacher. One of Bucer's first actions in the cause of reform was to debate with Thomas Murner, a monk who had attacked Luther in satires. While the city council vacillated on religious issues, the number of people supporting the Reformation and hostile towards the traditional clergy had grown. The hostility reached a boiling point when Conrad Treger, the prior provincial of the Augustinians, denounced the reformist preachers and the burghers of Strasbourg as heretics. On 5 September 1524, angry mobs broke into the monasteries, looting and destroying religious images. Many opponents of the Reformation were arrested, including Treger. After the council requested an official statement from the reformers, Bucer drafted twelve articles summarising the teachings of the Reformation, including justification by faith ("sola fide"). He rejected the Mass and Catholic concepts such as monastic vows, veneration of saints, and purgatory. He refused to recognise the authority of the pope and instead emphasised obedience to the government. Treger was released on 12 October and left Strasbourg. With his departure, overt opposition to the Reformation ended in the city. The reformers' first goal was the creation of a new order of service—at this time the Strasbourg reformers followed Zwingli's liturgy. They presented proposals for a common order of service for the entire Reformation movement to the theologians of Wittenberg and Zürich. In Bucer's book "Grund und Ursach" (Basis and Cause), published in December 1524, he attacked the idea of the Mass as a sacrifice, and rejected liturgical garments, the altar, and certain forms of ritual. It was also this publication that acknowledged the introduction of congregational German hymn singing in the city. (Only his preface to the 1541 "Gesangbuch" surpassed it in terms of musical significance.) By May 1525, liturgical reforms had been implemented in Strasbourg's parish churches, but the city council decided to allow masses to continue in the cathedral and in the collegiate churches St. Thomas, Young St Peter, and Old St Peter.