The name of Campiglia Marittima we have the first evidence as early as 1004 under the name Campillia derived from Latin campus, "field". In 1862 it was added the suffix of "maritime", ie Maremma. Starting from the eleventh century, we have witnessed a number of documents that the first urban settlement of Campiglia Marittima. In 1004 the monastery of St. Mary Serena received as a gift on the part of Chiusdino, half of the castle of Campiglia with its territory and the church. In the twelfth century, a part of Campiglia was donated to the monastery of St. Justinian in Crag, owned Gherardesca. In 1406 Florence conquered Pisa and Campiglia, transforming the fortress of Campiglia in an important outpost until 4 June 1509, when the Battle of Alvino, Campiglia slowly began to lose its importance, and this entailed a natural military and economic degradation. Its strategic importance gradually declined until 1664, when the land inside the walls of Castle Rock, was given rented as farmland.