How are the crusaders identified in the painting? by their armor by their weapons and horses by the red crosses on their backs by the thrones on which they are sitting

   By the red crosses on their backs

Explanation:  The Crusades were medieval Christian knights who took part in the holy war in the Middle East and the liberation of the Holy Land of the holy city of Jerusalem, which was under the rule of the Muslims. They were recognizable by the knights' armor, but given that all medieval knights wore armor, for example, with the emblem of the nobility or kingdom, the crusades had a red cross as a recognizable sign of purpose and struggle into which they were going to.