The Diocese of Saint-Omer is a Roman Catholic diocese located in northern France. Established in the 7th century, it covers the area around the city of Saint-Omer and is part of the ecclesiastical province of Lille. The diocese has a rich history and has played a significant role in the development of Christianity in the region. The diocese is known for its historical architecture, including the Saint-Omer Cathedral, which showcases various architectural styles. It also supports various parishes and religious communities, contributing to the spiritual life of the local population and promoting Catholic teachings and values.