Prophet Mohammad's Letter to the Monks of Saint Catherine's Monastery, Mount Sinai
In 628 AD, a delegation from St. Catherine’s Monastery visited Prophet Muhammed and requested for protection. The Prophet responded by granting them a charter of rights - copied below. St. Catherine’s Monastery is located at the foot of Mt. Sinai and is the world’s oldest monastery. It possesses a huge collection of Christian manuscripts, second only to the Vatican, and is a world heritage site. The original letter was taken away in 1517 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.
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 God! 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)."
For reference, see:
Prophet Mohammad's Promise to Christians by Professor Muqtedar Khan: http://www.middle-east-online.com/english/?id=36388
Institute of Arabic and Islamic Studies: http://www.islamic-study.org/saint_catherine_monastery.htm
YouTube clip of this historical document: http://www.youtube.com/watch?v=u0SsRmC6O5k
'Splendor in the Sinai' - A Research paper on the authenticity of the document: