Das Grabmal des Landgrafen Konrad von Thüringen. Neben dem Thüringer Löwen sieht man das Wappenschild des Deutschen Ordens, als dessen Hochmeister Konrad als direkter Nachfolger Hermann von Salzas zwischen 1239 - 1240 amtierte.
The tomb of the Landgrave Konrad of Thuringia. In addition to the Thuringian lion you see the coat of arms of the Teutonic Order, as its Grand Master Konrad as a direct successor of Hermann von Salzas officiated between 1239 - 1240.
Source: timediver - Hessen - Sankt Elisabeth Kirche - Marburg
Referenced for 'Teutonic Knight in Habit, 13th Century' in Armies of Feudal Europe 1066-1300 by Ian Heath:
This figure is from the tomb effigy of Conrad of Thuringia, Hochmeister of the Teutonic Knights 1239-41. Like the Templars - and despite their opposition - the Teutonic Knights wore a white habit, their right to this being secured for them in 1244 by Emperor Frederick II. Prior to this date, as is clear from this effigy and various other sources, though their mantles were white their tunics were grey