[1] The fortress was built on the remains of Tyras, an ancient Greek city on the northern coast of the Black Sea which existed until the 4th century.

[citation needed] After the territory came under the control of the Principality of Moldova, the Moldavians called it Cetatea Albă (literally White Citadel).

The fortress was built of white limestone, for which a mortar made of eggs, crushed marble, carbon, and silicon was used.

[citation needed] The cores inside the wall were shaped like a tetractys: a figure with ten points that form nine equilateral triangles.

[4] This confirms the view of some historians that the Bilhorod-Dnistrovskyi fortress was built by Freemasons and the incomprehensible portion was made specifically for the tetractys.

[citation needed] In the second half of the 15th century, the Moldavian principality was marred by a civil war between different factions, and king Bogdan II was murdered in an ambush by his brother Peter III Aaron in 1451.

Since Cetatea Albă was the main defensive center in the southeast of the state, located right on the trade route between Europe and Asia, it was given renewed attention under a new ruler.

The hardest siege was in August 1484, when a 300,000-man army of Ottoman sultan Bayezid II and 50,000 troops of the Crimean Khan Meñli I Giray, supported by over 100 large ships, besieged the castle from the coast and estuary.

Bilhorod was often a place of refuge during the campaigns, and the Crimean Khan İslâm II Giray even died in the fortress and was buried in the mosque, of which only one minaret now remains.

[citation needed] During the long Turkish domination, the Bilhorod fortress was repeatedly rebuilt and renovated with new fortifications.

The Russian invaders could not stay there long, and, according to Treaty of Küçük Kaynarca, finally returned to the city[clarification needed] in 1774.

In 1789, the town was captured without a fight by a large detachment of Don Cossacks and a Jäger (infantry) hunter corps headed by Mikhail Kutuzov.

The Ottoman period of Bilhorod ended in 1812, following the Russo-Turkish war of 1806-1812, when Russia took the eastern part of the Principality of Moldavia, between the Prut and Dniester rivers.

This treaty expanded Russian influence in the Danube region and established a framework for the eventual independence of Western Moldavia and Wallachia.

The pieces with the heraldic symbols of Moldova and the Moldavian Principality were removed by Soviet Authorities, with the Romanian state regaining it on 28 July 1941 during the invasion of the USSR in the course of the Second World War and had it within its boundaries until 22 August 1944 when the Red Army reoccupied the city.