Saturnin of Toulouse was one of the "Apostles to the Gauls" sent out during the consulate of Decius and Gratus (250–251) to Christianise Gaul after the persecutions under Emperor Decius had all but dissolved the small Christian communities. Fabian sent out seven bishops from Rome to Gaul to preach the Gospel: Gatien to Tours, Trophimus to Arles, Paul to Narbonne, Saturnin to Toulouse, Denis to Paris, Austromoine to Clermont, and Martial to Limoges. His feast day is 29 November.

Toulouse is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, 150 kilometres from the Mediterranean Sea, 230 km (143 mi) from the Atlantic Ocean and 680 km (420 mi) from Paris. It is the fourth-largest city in France after Paris, Marseille and Lyon, with 504,078 inhabitants within its municipal boundaries (2021); its metropolitan area has a population of 1.5 million inhabitants (2021). Toulouse is the central city of one of the 22 metropolitan councils of France. Between the 2014 and 2020 censuses, its metropolitan area was the third fastest growing among metropolitan areas larger than 500,000 inhabitants in France.