So many other great comments about this. It should be a rainbow light saber. The Farce is strong with this one. He should be Jedi master Oh Mai. Make it so! They go on and on.
It was common at the time for artists to imagine ancient times to be similar to their own. Aside from cultural norms that shaped their art, research for historical accuracy would have been a daunting task.
I think that Joseph is using a plane.