The First Panzer Division was created from independent motorized and armored components on April 17, 1941, just 2 months before it would go into combat. It was assigned to the Army Group Antonescu, in the Romanian Cavalry Corps (or RCC), which operated under the German 11th Army. Divided into several mobile groups, the division participated in the northern penetrations into Bessarabia, the area the Soviet Union had taken from Romania in 1939. It was during this campaign that the speed deficiencies of the R-35 became obvious. They simply were unable to keep up with any mobile operations and could barely keep up with the advancing infantry. During these operations, the 1st Panzer was used continuously in flank attacks with much success. Bessarabia was liberated by July 26, 1941 and the 1st Panzer went into refit mode for the next two weeks.
It was the first Romanian unit to take part in the invasion of the USSR. After Odessa was captured, the detachment was disbanded. During the first campaign, the 1st Armored Division lost: 34 officers, 102 NCOs, 1,125 soldiers, 463 rifles, 54 LMGs, 5 HMGs, 206 vehicles and 111 tanks. It was refitted during 1942 and later fought near Stalingrad suffering very heavy losses before being sent back to Romania to be rebuilt.
It spent 1943 and 1944 being refitted as well as training with other parts of the Romanian army until it was reestablished as a division Apr 1944 and given the honor title Rumania Mare (Great Romania). It returned east to fight the Red Army and continued to do so until the Romanian defection of the Axis camp Aug 1944.
Information copied from various internet sources