==Wording== 

 This phrase confused me on first reading: 

 :Surfaces like shields — both those used in tournaments and those hung as decorations — were more durable 

 Somehow I thought that "shields" meant a protective coating like lacquer over the painting, like glass in a picture frame. You meant a military shield used in combat - like Aragorn in Lord of the Rings, knights in shining armor trying to slice or skewer each other with swords. 

 Maybe re-casting this sentence from the passive voice? Like: 

 *Knights decorated their shields with oil painting - instead of tempura - because . . .