The catalan atlas emphasized the preeminence of which western sudanic king

Mansa Musa was Mali’s leader who led the people as the king. He was showed his sitting on a gold throne by Catalan. They created wealth within a short period by heavy taxing traders in his kingdom. This is because his country had become an essential route for trading; some of those routes were those from the Trans Saharan regions. However, the kingdom of Mali under the leadership of Musa did not last because of unfortunate ruling and administration that occurred because of Songhai empire encroachment.

this is a good question! i'll do some research and come back when i have the answer!

the crusaders are identified in the painting;

c. by the red crosses on their backs