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:
Křivoklát Castle was founded in the 12th century, belonging to the kings of Bohemia. During the reign of Přemysl Otakar II a large, monumental royal castle was built, later rebuilt by king Václav IV and later enlarged by king Vladislav of Jagellon.
The castle was damaged by fire several times. It was turned into a harsh prison and the building slowly deteriorated. During the 19th century, the family of Fürstenberg became the owners of the castle and had it reconstructed after a fire in 1826.
Today the castle serves as a museum, tourist destination and place for theatrical exhibitions. Collections of hunting weapons, Gothic paintings and books are stored there.