The Letter Reads:
This is a message from Muhammad ibn Abdullah, as a covenant to those who adopt Christianity, near and far, we are with them.
Verily I, the servants, the helpers, and my followers defend them, because Christians are my citizens; and by Allah! I hold out against anything that displeases them.
No compulsion is to be on them.
Neither are their judges to be removed from their jobs nor their monks from their monasteries.
No one is to destroy a house of their religion, to damage it, or to carry anything from it to the Muslims' houses.
Should anyone take any of these, he would spoil God’s covenant and disobey His Prophet. Verily, they are my allies and have my secure charter against all that they hate.
No one is to force them to travel or to oblige them to fight.
The Muslims are to fight for them.
If a female Christian is married to a Muslim, it is not to take place without her approval. She is not to be prevented from visiting her church to pray.
Their churches are to be respected. They are neither to be prevented from repairing them nor the sacredness of their covenants.
No one of the nation (Muslims) is to disobey the covenant till the Last Day (end of the world).
St Catherines monestary has this to say about their letter:
“According to the tradition preserved at Sinai, Mohammed both knew and visited the monastery and the Sinai fathers. The Koran makes mention of the Sinai holy sites. In the second year of the Hegira, corresponding to AD 626, a delegation from Sinai requested a letter of protection from Mohammed (saw). This was granted, and authorized by him when he placed his hand upon the document. In AD 1517, Sultan Selim I confirmed the monastery’s prerogatives, but took the original letter of protection for safekeeping to the royal treasury in Constantinople. At the same time, he gave the monastery certified copies of this document, each depicting the hand print of Mohammed in token of his having touched the original. ”
(taken from yursil)