Bayonne has been inhabited since roman times, when it was known as Lapurdum. Its medieval fortifications were improved by Louis XII, and Francois I, enabling the town to defend itself against a Spanish army in 1523.
Vauban visited Bayonne sometime in the 1670's, and planned more improvements to the fortifications, including the construction of additional demi-lunes and a large, quadrangular citadel to the north of the river Adour. The city itself, which lies to the south of the Adour and is bisected by the river Nive, was surrounded by a wall of 9 rather eccentric bastions.
The citadel was designed from scratch by Vauban, and is a large square work with four bastions. It saw action against the invading British forces at the end of the Peninsular War, when it was taken by General Hill after a determined defence by the French.
The fortifications of Petit Bayonne, the eastern half of the town, had four bastions and one gate, the Porte de Notre Dame. To the west, Grand Bayonne had five bastions and two gates, the Porte d'Espagne and the Porte de la Poterne. The first gate is unusual in that it enters the walls through a bastion, not through the courtine as is normally the case.
The size and shape of each bastion is very different, and there are varying lengths between them, which makes the fortifications seem less regular than some. This is probably due to the way Bayonne was fortified in several stages, with improvements added gradually.References:
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.