In the library of the monastery of St. Catherine’s Sinai is a copy of a document signed by the Prophet Muhammad in 628 C.E. It is a Charter of Privileges for Christians.

In 1517, the original letter was taken by the Turkish Sultan Selim I and is now in the Topkapi Museum in Istanbul, but the sultan gave the monks a copy of it and sanctioned its terms. The privileges of protection and safe-conduct for the monks have been upheld to this day.

English translation from 'Muslim History: 570 - 1950 C.E.' by Dr. A. Zahoor and Dr. Z. Haq, ZMD Corporation. P.O. Box 8231 - Gaithersburg, MD 20898-8231 - Copyright Akram Zahoor 2000. P. 167.
http://www.cyberistan.org/islamic/charter1.html