The attitudes of Christianity and Islam toward merchants

Islam and Christianity share a lot of similarities and differences. One of the most important similarities that they share is that they are both universal religions. Both Islam and Christianity are monotheistic religions, believing in only one god, which is also believed by some religions researchers to be the same god, but referred with different nominatives. In the Christian religion it is referred to as "Christ" and in the Islam religion it is referred to …

…of trade according to Christianity, I would need an additional document that describes if the Christians merchants took advantage of the situations to cheat on their costumers or if they respected the new developments: trade was allowed as long as the merchants were honest between each other. If I would have the opportunity to have that document I could make a final affirmation about the developments of Christianity from the early years until 1500 C.E.