Giovanni II Paleologo, Marquis of Monferrato, ordered to build the current castle in Casale Monferrato and the work continued until 1357. When Casale assumed the role of capital of Monferrato's marquisate and obtained in 1474 the title of city, also the castle, seat of the court, changed its aspect following the restoration with the Marquises Guglielmo VIII (1464-1483) and Bonifacio V (1483-1494).
When Giovanni II Paleologo died, the Gonzaga of Mantova took charge of Casale. Because of the new military techniques the castle was reinforced. They strengthened the walls and the plan form was modified, becoming hexagonal (we can still see it). The towers were reinforced too and four new ravelins were added. At the beginning of the 17th century the castle returned to assume the role of seat of the court: indeed, the Dukes of Mantova, busy in frequent negotiations with Savoy, sojourned there. Later it became the principality of the Duke Carlo II Gonzaga-Nevers (1637-1665), who many times was there in vacation with all his court, giving a considerable impulse to the elite and cultural life of Casale.
With the crisis of the Gonzala's dynasty, the castle was about to face an unstoppable decline. The city fell into Savoy's hands in 1708 and the castle became a barracks.
In the middle of the 19th century Casale was fortified in preparation for a war against Austria and the castle became a defensive structure. The state of Savoy decided to demolish the eastern ravelin, which pointed towards the city allowing the creation of an extended public area (today's piazza Castello). The municipality designated this area as an open-air market zone. With the advent of the Unity of Italy the other three ravelins were demolished too, because they were unnecessary.References:
Goryōkaku (五稜郭) (literally, 'five-point fort') is a star fort in the Japanese city of Hakodate on the island of Hokkaido. The fortress was completed in 1866. It was the main fortress of the short-lived Republic of Ezo.
Goryōkaku was designed in 1855 by Takeda Ayasaburō and Jules Brunet. Their plans was based on the work of the French architect Vauban. The fortress was completed in 1866, two years before the collapse of the Tokugawa Shogunate. It is shaped like a five-pointed star. This allowed for greater numbers of gun emplacements on its walls than a traditional Japanese fortress, and reduced the number of blind spots where a cannon could not fire.
The fort was built by the Tokugawa shogunate to protect the Tsugaru Strait against a possible invasion by the Meiji government.
Goryōkaku is famous as the site of the last battle of the Boshin War.