Where does this phrase comes from, and how can it be religion of peace if Mohammed himself was a war-general ?
Ok, this question has been reported, and I can understand why. But asking about when the particular phrase 'religion of peace' became attached to Islam is a legitimate question. That said, the answer may violate our 20 year rule (I honestly don't know if the phrase is older than 20 years or not).
The phrase "religion of peace" likely has a long history, but it's modern polemical undertones (whether for or against Islam) are a post-9/11 phenomenon. George W. Bush is credited with popularizing it, and it's been controversial ever since. It's from his "Islam is Peace" speech six days after the 9/11 attacks:
The English translation is not as eloquent as the original Arabic, but let me quote from the Koran, itself: In the long run, evil in the extreme will be the end of those who do evil. For that they rejected the signs of Allah and held them up to ridicule.
The face of terror is not the true faith of Islam. That's not what Islam is all about. Islam is peace. These terrorists don't represent peace. They represent evil and war.
When we think of Islam we think of a faith that brings comfort to a billion people around the world. Billions of people find comfort and solace and peace. And that's made brothers and sisters out of every race -- out of every race.