In 1719, the Swedish Order of Knighthood had already prepared a forward-looking report on new defense arrangements, and the state commission's fortification program of 1721 mentions a border fortress to be placed in Finland. Löwen suggested Weckelax Nystad (Vehkalahti) as the location for the main fortress. A strong fortress was needed to control the coastal routes and connections to inland, as well as to protect the population and commerce of the rebuilt city. According to Löwen's plan, a large city fortress was to be built, the fortifications of which would be based on the bastion system considered the best in Europe at the time

A new edition of Daniel Speckle's book on fortifications, "Architecrura von Festungen", had just appeared during Löwen's time. In it, Speckle improved the 17th century bastion system and accurately described the Palmanova fortress built at the end of the 16th century. The fortress town of Palmanova, located in northern Italy, close to the Slovenian border, can be considered a model for Hamina.

In Hamina's symmetrical fortress plan, the circle was geometrically divided by squares in such a way that an octagonal polygon was created. Ramparts, or bastions, protruded from the corners of the main wall, the cannons placed on the sides protected the adjacent bastions. The same basic octagonal shape was also applied to the layout of the city inside the fortress, where the central square was surrounded by ring streets and from which radial streets started. Hamina and Palmanova in Italy are only European star-shaped fortress towns, with a circular town plan.

The star-shaped fortress of Hamina managed to be built in its shape during the Swedish rule, but due to the lack of funding, the ramparts remained relatively low, and no stone walls were built to support them yet. The fortress town of Hamina, which had been renamed Fredrikshamn in 1723 after King Fredrik I of Sweden, was placed on a peninsula between the sea and Lake Kirkkojärvi. Because they wanted to accommodate a large enough city and garrison inside the ramparts, the fortress became too large for its location. For this reason, two bastions from the northeast side of Kirkkojärvi were left out and they were replaced by a rampart built on top of a steep bank. The seventh bastion of the fortress, the Central Bastion, was built only at the beginning of the 19th century

When the War between Sweden and Russia (1741-1743) broke out, the fortress was still badly outfitted. The faith of the own troops in the defense capabilities of the fortress was shaken and the city was handed over to the Russians without a fight in 1742. The Swedes set the city on fire and retreated west. Estimates of the city's destruction differ widely in Swedish and Russian sources, but it is certain that the most valuable part of the city inside the fortress was either destroyed or at least badly damaged. However, claims of the city's complete destruction are exaggerated.

When Suvorov left Hamina in the fall of 1792, his work was continued by General Jan Peter van Suchtelen, under whose leadership the current Kyminlinna fortress was also built. In Hamina, van Suchtelen strengthened the front section of the fortress on the Kirkkojärvi side by replacing the rampart with a large Central Bastion and building caponiers on both sides of it, as well as an arrow-shaped fort acting as an outpost to the north of the main fortress. The caponiers represented a new kind of defense thinking for us, where the main focus of the artillery was placed in separate gun positions built in the moat instead of bastions. Central Bastion, which functions today as an event arena, was first of all a depot, which housed 58 bomb-proof vaults, or casemates. On top of the casemates, firing positions were reserved for riflemen only.

By 1808, Hamina's star fortress was practically complete. In the 19th century, the fortress was surrounded by the so-called the fortress esplanade, an unbuilt area about 240 meters wide, which was also leveled so that the enemy was left with no protection of any kind. Three main gates led to the fortress. The large coastal road passed through the gates of Lappeenranta and Vyborg. There was a third gate along the current Maariankatu, through which the port was reached.

The Finnish War (1808-1809) again changed the military-political position of Hamina. Russia conquered all of Finland up to the Tornionjoki valley. The peace that ended the war was concluded in Hamina in 1809, and the entire country was annexed to Russia for over a hundred years.

Hamina's fortifications continued until 1811. However, with the development of military technology, defense systems like Hamina's star fortress gradually began to lose their importance, and in 1835 the fortress was transferred to the "second class" and handed over to the city. In accordance with the maintenance obligation, the fortress had to be maintained and nothing could be dismantled.

The last time the fort was needed militarily was during the Krimean War in 1855, when there was a firefight with the English navy. It was not until 1878 that the city was granted final rights to the entire area of the fortress. After this, the Hamina fortress was allowed to deteriorate until the second half of the 20th century, until it was restored in collaboration with the Finnish Museum Agency, the city of Hamina, the Ministry of Justice and the Ministry of Defense, a decades-long project almost like the original.

Hamina remained as a military town even after the fortress lost its importance. Along with the Russian garrison, Hamina Cadet School operated in the city between 1821 and 1903. The school was intended for talented boys of the Finnish nobility, who could start their studies in elementary school already at the age of 8-12. About 40 students were admitted to the actual Cadet School course each year. The age