Bordering the banks of the Gironde estuary, this small town was for centuries a principality, a title it acquired after the Hundred Years War, but ended up losing by escheat.

[3] The origins of St. Stephen's church date back to at least the 12th century, although it hardly remains of elements from that period, except a few walls (parts of the apse and transept) and a series of capitals at the braces (listed historical monument).

Burned and looted during the Wars of Religion by the troops of Agrippa Aubigné, it was rebuilt once peace returned, but again in very bad condition in the early 18th century.

Two architects differ as to the party to implement Gustave Alaux, follower of neo-Gothic style, and Antoine Brossard, holding of neoclassicism.

The proposed Alaux finally won, and in 1859 the bell tower Bourg stone, crowned with an arrow used to Mariners bitter, was built.

Since summer 2003, Mortagne-sur-Gironde has set up a small local museum located in the old pier of the current marina, which traces the history of the village through an original background 300 reproductions old postcards .