After the Sweden's defeat in Russo-Swedish War 1741-1743 (also known as the Hats' Russian War) eastern border of Finland was moved to west. Important fortresses of Hamina, Lappeenranta and Savonlinna were left to Russian side of border.
The city of Loviisa was established in 1745 to handle a international commerce in Finland. Planning of the new fortification system started concurrently, because Loviisa was located alongside the strategic road from Vyborg to Turku. The parliament accepted the plan of twin fortresses in 1747: one in Loviisa city to protect the road and another to Svartholma island to defence Loviisa from the sea. Building of the Loviisa fortress started in 1748, but the plans were never completed. The ground was too muddy for heavy stone walls and the Crown had continuous lack of money. Building was interrupted in 1757 and the king Gustav III ordered to stop the construction permanently in 1775. Loviisa fortress didn't see any battle. In the Finnish War 1808-1809 it surrended to Russians without fighting, because people of Loviisa were afraid of the destruction of the city.
Nowadays there remains two completed bastions, Rosen and Ungern. Renovation started in the 1960's and Ungern is mostly renovated. Rosen is still uncompleted and mostly ruined.
The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.