Yep, Jim & Desdemona are on it. The Crusades were originally Ethopians who went out to turn people into Christians--and they really got around. After Christianity was well established and the Crusades were common, they extended back into the middle east, and the slaves & other "trade goods" were brought back (before some of you scream prejudice, this is NOT an editorial comment, only a statement of historical fact!!). The human beings who were slaves were also undoubtedly musicians & dancers and shared their music. There is always going to be some mixing it up when you have some folks traveling about, and some of the men in charge no doubt liked the "exchange" of culture. The musical instruments were found during the travels, and the music came out of that influence also, as others suggested above. The modern scale which we use is based on the major tonality, but the scales used in the rennaisance was based partly on the modes and after much time worked into the Major scale as we know it. The instruments brought back on travels in other eastern countries were lute & oud like, and also there was a shawm like (or sort of oboe like) "screamer", which was like the bombarde and used for belly dancing, and still is, and then lots of fascinating drums & cymbals, very common in eastern music. These wonderful instruments and other things influenced the music, playing those instruments in the Rennaisance style would have been quite a curiosity in the time. The Rennaisance was a time in history when travel was important in the form of discovering & taking over other societies, and part of that is going to be bringing back things considered exotic compared to ones' normal tastes--teas, spices, silks, gems, beads, glass, wines & other forms of alcoholic beverages, gunpowder, & fireworks were very popular. And yes, it is interesting to see the things which influence the direction which music flows in various times & cultures.