The former abbey church of Saint-Sernin in Toulouse - now known as the Basilica of Saint-Sernin - was built between about 1080 and 1120, and restored by French architect Viollet-le-Duc during the nineteenth century. The cartulary of the abbey, which contains copies of all the charters and records relating to the institution, was established between 844 and 1200, and transcribed by several copyists at the end of the twelfth century. It went missing for several centuries, but was rediscovered in 1885 by Celestin Douais (1848-1915), a priest and professor of ecclesiastical history at the Institut Catholique of Toulouse. Originally published in 1887, Douais’ scholarly edition of the Saint-Sernin cartulary was the first to make these important documents available to the public. It provides valuable information on the history of the abbey, and remains an essential resource for palaeographers and medieval historians.