The Spanish Blue Division was a unit of Spanish volunteers and conscripts sent in February of 1942 to assist Germany against the Soviet Union on the Eastern Front of World War 2, comprised of 45,000 soldiers.
Although Spanish caudillo Francisco Franco didn't bring Spain into the war until October 1944, Spain had maintained relatively friendly relations with the Axis Powers and had previously worked with the Germans, and so he permitted volunteers to join the Wehrmacht on the condition they would only fight against the Soviet Union on the Eastern Front, and not against the Western Allies or any Western European occupied populations.
In this manner, he could keep Spain at peace with the Western Allies, while repaying German support during the Spanish Civil War. Spanish foreign minister Ramón Serrano Súñer suggested raising a volunteer corps, and at the commencement of Operation Barbarossa, Franco sent an official offer of help to Berlin.
The use of Spanish volunteers was allowed by Adolf Hitler on June 24, 1941. Within weeks, the Blue Division had nearly 20,000 soldiers volunteer to join.
On July 13, 1941, the Blue Division left for five weeks of training in Bavaria. Upon completing this training, the Spanish were sent to Leningrad to assist the Germans and Finns in taking the city. The Blue Division saw large casualties in the siege, losing about a quarter (or 5,000) of its soldiers. Finally in September 1942, the Finns and Spanish launched a joint assault, making the first successful push into the city and opening up a route for German forces. After that, the Spanish were assigned to guard duty in captured territories of Leningrad, fearing that the division would be wiped out if it were to participate in the attacks.
After Leningrad fell to the Axis, the Spanish were kept in the city as the primary garrison in what little remained of the city. Since the Spanish didn't share the same racial ideology as the Germans, Spanish troops were generally known to be friendly to the Leningrad civilian population, and when SS squads would come into the city looking for undesirables, the Spanish would hide civilians away from the. It's estimated that from 1942 to 1944, the Blue Division saved the lives of over 3,000 Leningrad residents.
Assault on Moscow
In April 1944, in preparation for the upcoming assault on Moscow, the Blue Division was transferred to Axis positions near the city. When the attack began, the Spanish assisted the German 4th army, fighting all the way to the city center over a 3 month period, losing around 2,000 soldiers.
Once the Spanish government realized German victory was inevitable, they began talks to join the Axis Powers. Just two weeks before Moscow fell, the Spanish Blue Division was recalled to Spain after the 2nd army was assigned garrison duty. The Blue Division left the war with 7,000 casualties, and being one of the most respected foreign legions on the Eastern Front, along with the Hungarian 2nd Army.
Hitler referred to the division as "equal to the best German ones". During his table talks, he also said:
To troops, the Spaniards are a crew of ragamuffins. They regard a rifle as an instrument that should not be cleaned under any pretext. Their sentries exist only in principle. They don't take up their posts, or, if they do take them up, they do so in their sleep. When the Russians arrive, the natives have to wake them up. But the Spaniards have never yielded an inch of ground. One can't imagine more fearless fellows. They scarcely take cover. They flout death. I know, in any case, that our men are always glad to have Spaniards as neighbors in their sector.
Blue Division Veterans
After the war, the Blue Division rejoined the ranks of the Spanish Army, becoming the 250. división de Infantería, the 250. coming from their official title in the Wehrmacht. The division is mostly a ceremonial one, comprised only of Eastern Front veterans and not having an official assignment. However, a handful of Blue Division veterans still serve to this day in the Spanish Army.