The T-54 and T-55 tanks are a series of main battle tanks (according to some sources) although not recognized as MBT by Soviet and Russian sources, instead classifying them as medium tanks. (the very concept of “main battle tanks” was applied only to tanks beginning with T-64A, armed with 125-mm tank gun) that were designed in the Soviet Union.
The first T-54 prototype appeared in March 1945, just as the Second World War ended. The T-54 entered full production in 1947 and became the main tank for armored units of the Soviet Army, armies of the Warsaw Pact countries, and others. T-54s and T-55s were involved in many of the world’s armed conflicts during the late 20th and early 21st century.