Petrusse Casemates origin goes back to 1644, when the Spaniards reinforced the medieval fortifications. Under the supervision of the Swiss fortress builder Isaac von Treybach, they built - among other defence works-the powerful Beck Bastion, named after Governor Baron Johann von Beck, a native of the city who had played a key role in the Wallenstein affair on the side of the Emperor. Initially this bastion was as high as the adjacent terraces on the right; it was raised to the present level of Constitution Square (the wall is 27 meters high) by Vauban in 1685.
In 1673 the Spaniards erected the so-called 'Ravelin du Pate' to strengthen the defence of the Beck Bastion; this triangular construction is one of the few well-kept fortifications. Marshall de Vauban conferred the present shape to all the Petrusse fortifications and built the 'Small Staircase'. From 1728-29 the Austrians added the 'Bourbon Lock' and the 'Large Staircase' and in 1746 the casemates of the 'Petrusse Battery' (54 gun emplacements).
One century passed and the fortress was enlarged and reinforced: the second ring was extended and the third started, so that Luxembourg became the 'Gibraltar of the North'. By and by, the Petrusse fortifications fell into oblivion and neglect, as their strategic momentum limited itself to the valley. After the dismantling, stipulated by the 1867 London Treaty, they confined themselves to walling up the loopholes and most entrances. In 1933 the Petrusse casemates were opened to the public.References:
The Château des ducs de Bretagne (Castle of the Dukes of Brittany) is a large castle located in Nantes. It served as the centre of the historical province of Brittany until its separation in 1941. It was the residence of the Dukes of Brittany between the 13th and 16th centuries, subsequently becoming the Breton residence of the French Monarchy. Today the castle houses the Nantes History Museum.
The restored edifice now includes the new Nantes History Museum, installed in 32 of the castle rooms. The museum presents more than 850 objects of collection with the aid of multimedia devices. The castle and the museum try to offer a modern vision of the heritage by presenting the past, the present and the future of the city. Night-time illuminations at the castle further reinforce the revival of the site. The 500-metre round walk on the fortified ramparts provides views not just of the castle buildings and courtyards but also of the town.