What was wrong with Columbia's ideas about the world during his trip

there was a piece of land blocking his way from getting to where he needed to go

Explanation:

when your a dog and you need a bone.   go and eat a rabbit

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.