Ymir, although the video Tlaloc posted was pathetic, if you look at how the Islamic empire spread, which is the only correct thing in that video, it was towards the Empires that threatened Islam with war. They fought Persia (the land east of the Arabian peninsula), the fought the Romans (the land north and north west, ie south western Asia (Turkey) and southern Europe) and they fought the a few other empires in Africa with whom Muslims had fought before due to a messenger which our Prophet sent to them being murdered as a result the battle of Mutah happened.