Souesmes must have had some importance towards the end of the 8th century since during the division of the archbishopric of Bourges into archdeaconries themselves divided into archpriests, the priest of Souesmes received the title and function of archpriest. This archpriesthood included 32 parishes, all located to the east of Souesmes (except Salbris). It extended as far as the Loire to the northeast and to Boisbelle (Henrichemont) to the southeast as recalled by the table drawn up by Canon Augustin Petit, priest of Souesmes from 1892 to 1948, according to documents found in the archbishopric of Bourges. This table is still in place at the entrance to the church. The left side of the choir of the church of Souesmes is placed under the protection of Saint Julien, beheaded in Brioude around the year 304. The original building was no longer sufficient for the development of worship, which is why a larger Romanesque-style church was built on the same site during the Carolingian era. The walls of the nave bear witness to this period, the six windows being very small at the time. Carolingian terracotta modillions found in the walls during work in the 19th century allow us to date the period of construction of the walls. One of the modillions is in the Museum of Religious Art in Blois and two others, owned by SAHAS, are in the Marcel de Marchéville Archaeological Museum in Romorantin-Lanthenay (article by Joëlle Fallot - Jean-Marie Lorain published in the booklet "Souesmes heritage in your commune" produced by the departmental committee for heritage and archaeology in Loir-et-Cher and the municipality of Souesmes with the assistance of the general council of Loir-et-Cher).