The Teutonic Knights were one of the religious orders formed during the crusades, by a group of Germans serving in the Holy Land.
After the defeat of the western nations during the crusades, they eventually set up base in the region which eventually grew into the Kingdom of Prussia. Although they seem to have started off with reasonably good intentions, as time went by they followed the path of most of the other religious fighting orders of the day and became more a band of armed thugs throwing their weight around and trying to build their own little empire, than the "upholders of Christianity" they were supposed to be.
The knights were pretty much dealt to on July 10, 1410 at Tannenburg by an Eastern European alliance, and although the order continued, they had lost their power. The knights themselves were never great in number, with only about 350 kinghts at their peak. But they owned vast lands, and hired those out to tennant knights, who then fought for their cause.
Their "black cross on a white background" was the forerunner of the German "Iron Cross" during World War II, and indeed, when the Germans fought the Russians at Tannenburg in WWII, many Germans looked on the battle as "revenge for 1410!".
In the photos above, the Teutonic Grand Master leads some of his Bretheren Knights onto the attack. When I first painted up my Grand Master I was really pleased with the way he turned out, although now, comparing him against my Russian and Mongol generals, he looks very ordinary.
A funny story about this lot. When I first had them ready for battle, I had a system of "chance events" in my wargames rules, which called for "unusual" things (out of left field, that COULD happen, but you wouldn't expect it). Basically on each turn I rolled two dice, and if a "double" came up, one unit (decided by another dice throw) then performed one of a number of actions (again decided by another dice throw).
In each of their first three battles, my Teutonic Knights managed to find a cellar full of alcohol in a nearby town/farm house and stopped fighting to go on a drinking binge! They didn't just do it ONCE - they did it THREE times, which really pushed the laws of probability.
Needless to say I was not impressed! They have improved, but not yet to the point that they are my star performers. We'll see if they can do any better next time out!