DaVince's "Last Supper." :  Da Vince lived long after Jesus so his painting would have little to do with what happened apart from reading the Gospels and putting his interpretation on canvas. While I don’t hold with any notion of Jesus bearing children from anyone, although I cannot consider that that would be sinful in any way, I am sure it was not his purpose and did not happen. However his relatives, cousins, aunts uncles etc and their bloodline would have been seen as very important and Da Vince may well have with his connections  encoded linkages to such within his works.