Army Group Courland ended in 1945.
Sixth United States Army Group ended in 1945.
Two theories which can operate in tandem or separately: Hitler wanted to keep his army in the Courland in the vain hope that it would act as a threat to the Russian right flank when he was able to counter-attack. The second theory is that he wanted to keep control of Baltic coastline so that his UBoats, especially the new type XXI could train. They would be part of his new UBoat assault that he hoped would turn the war around. As we see in both cases Hitler was suffering from some delusions.
In the 1930's until the end of WW2, it was the Imperial Japanese Army.
Army Group Don was created in 1942.
What a group of warriors is called generally depends on the size of the group. A small group is a squad. A somewhat larger group is a platoon or company. At the far end of the spectrum is an army.
Army Group Courland was created in 1944.
Bishopric of Courland ended in 1562.
Army Group Ostmark ended in 1945.
Army Group Vistula ended in 1945.
Army Group Don ended in 1943.
Army Group Liguria ended in 1945.
Alexander of Courland was born in 1658.
Alexander of Courland died in 1686.
Bishopric of Courland was created in 1234.
Army Group South Ukraine ended in 1944.
Southern Expeditionary Army Group ended in 1945.
Princess Dorothea of Courland was born on 1793-08-21.