Their cultivation of science dates from the capture of Alexandria, A.D.638.

This was only six years after the death of the Prophet.

In less than two centuries they had not only become acquainted with, but correctly appreciated, the Greek scientific writers.

As we have already mentioned, by his treaty with Michael III., the khalif Al-Mamun had obtained a copy of the "Syntaxis" of Ptolemy.

He had it forthwith translated into Arabic.