Two blue horses in front of a red rock

This is a postcard. On the 21st of May 1913 Franz Marc painted these two blue horses on a small card at Sindelsdorf, the village in the Bavarian foothills where he lived, and mailed it to his friend Wassily Kandinsky in Munich. The two men were the heart of the Blue Rider, the circle that had just shaken up German art, and they wrote to each other constantly, often on cards Marc painted by hand. Blue was not decoration for him. He and Kandinsky treated colour almost as a code, and blue stood for the austere, spiritual side of things, which is why his horses so often wear it. Barely the size of your palm, it went out through the ordinary post in the spring before the war that would kill him at Verdun three years later.