In 1283, Dinan became a ducal town and work started on the ramparts, heralding a military role for the town which would last until the 20th century. Improvements to the fortifications continued until the 16^th century by which time they had reached 2650 meters in length. These defensive measures proved successful during the Ducal War of Succession when the town stubbornly resisted a siege by the English.

In the 17^th and 18^th century, Dinan developed much as other average-sized towns. There was growing concern over public health, luxurious private mansions were built along the major streets and numerous new convents appeared.

Despite the beginnings of a relative economic decline linked to the industrial revolution, the 19^th century saw the inauguration of the viaduct in 1852 and the construction of new parts of town. In 1879, the first station was built outside the walls and British incomers progressively settled in the town. As a result, an Anglican church was built.

The transmission of this living heritage has now been secured for the inhabitants and the 500 000 tourists welcomed every 2 year as the famous “Fete des Remparts” (Ramparts Festival) testifies.

A town of traders, craftmen and fairs since the Middle Ages, Dinan has succeeded in maintaining its role as commercial capital of the Rance Valley