They were named Ion C. Brătianu, Lascăr Catargiu, Mihail Kogălniceanu and Alexandru Lahovari.

Later, they contributed to the halting of the Central Powers' advance into the Danube Delta and held the line against the German forces in Moldavia during the summer and fall of 1917.

[8] On 22 and 23 June 1941, at the start of Operation Barbarossa, Mihail Kogălniceanu, aided by another Romanian monitor, Basarabia, and four patrol boats, managed to repel two Soviet attacks, sinking one patrol boat and damaging another two as well as two Soviet monitor.

[9] On 24 August 1944, Lascăr Catargiu and Mihail Kogălniceanu were sunk by Soviet aircraft.

The two ships were eventually returned to Romania on 23 June 1951, and the sunk monitors were also refloated.