Columbus, based on several biographies, was from Genoa. And an often used shorthand, Genevoese, referring to Jewish Italians is common, yet I believe that there isn't any evidence that he was Jewish. Will Durant in his "Story of Philosophy" speculated on this as well suggesting that 1492's Voyage to the New World was not a search for riches but for a refuge for the Jews as the date coincided with the beginning of the Inquisition in Spain. Would appreciate references for Columbus and DaVinci as well.
Here's a LINK to one of many online articles based on those 2 books.
As for Jawabac's swipe against America - "residents of Iroquois territory" - the Iroquois nation was itself built on warfare against other tribes, enslavement of the conquered and occupation of their lands. Many other Native American tribes were wiped out by the Iroquois. They make a poor choice for poster children against the morality of colonial European Americans.
The slaves from those areas also included Muslims. = The slaves from those areas also included Muslims & Christians.
Columbus is ambiguious
http://www.closetotorah.com/archives/1328
DaVinci is pretty much common knowledge that his mother (essentially a house maid) was the Jewish “girl friend” of his fahter.
http://www.closetotorah.com/archives/1328