While the builder of the Aarberg Castle is unknown, the city itself was founded between 1220 and 1225 by count Ulrich III of Neuchâtel. The count had recently acquired the rulership over this region and needed a central location from which to rule. The island and the key bridge was a natural location for a town. The castle may have been built around the time of the founding of the city.
The city was besieged in 1339, 1382 and 1386 but not taken. In 1358 the Graf (or Count) Peter von Aarberg was in financial difficulties and began looking for someone to buy the city. After years of unsuccessful attempts, in 1377-79 he was able to sell the city and his rights as ruler to Bern. The Bernese bailiff took up residence in Aarberg Castle in 1379. In 1380, the old castle roof was replaced with a new shingle roof. In 1419 and again in 1477, the town and castle of Aarberg were nearly destroyed in a fire. Both the town and castle were rebuilt following the destructive fires.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.