To answer this question I went to the masses, ie the climbing newsgroups, to get the opinions of many. Its a very hard question to answer, mainly due to the fact that the term Rock Climbing can mean anything. Below are the best answers I got. Wether it clears anything up, Im not sure, but at least its a start....

Origins of rock climbing... That's a bit like asking what the origins of hiking are. It's important to start by asking what you mean. Does Hannibal crossing the Alps count? Probably not.
I would say that the obvious starting point for rock climbing as opposed to mountaineering would be the 1492 ascent of... Mont Aiguille I think. This ascent was commemorated in 1992 with Christophe Profit and another famous climber putting up a new route on the same rock. The original ascent involved lots of what we would call aid - at the time that mostly meant ladders and various scaffolding - to get over the hardest parts.
The source I would look for first is Josias Simler's book on moutaineering from the late sixteenth century. It's in latin, but I think there has been a translation. It's generally considered the first book on mountaineering in a form that we would recognize.

Ergophobe

Hold the Heights by Walt Unsworth has a good bit of history of Mountaineering - dating way back (1400s) to when French priests/scientists would climb in the Alps to take "measurements" of different things. But I guess they quickly took to climbing for the fun of it, which the church often didn't like. It's been a while since I read it, but I remember enjoying it.

jason

Well there are instances of climbs being made for religious purposes going back several thousand years. For "pure" sporting purposes however we only need to go back to 1492 and the first ascent of Mt Aiguille by Antoine de Ville. However Mt Ventoux had been ascended in 1336 "for no other reason than to reach the summit". This is more of a walk than a climb however.
There were undoubtedly also many ascents made long before climbing became a sport for basic survival. I.e. hunting and shelter. The best known British example is St Kilda where the sea stacks were climbed in order to "harvest" the nesting birds. In fact the St Kildans, who climbed barefoot, had toes that had adapted to this that were both longer and stronger than the general population.
For a "sporting" answer then it is 1492. A more general answer is before recorded history.

HTH

Petrach in 1336 climbed Mount Ventoux, which some reckon to be the first "ascent".
But Po-Chu-i (772-846) wrote a poem "Having Climbed to the Topmost Peak of Incense Burner Mountains" containing the words "I clung to dangerous rocks; my hands and feet - weary with groping for hold". There are lots more early quotes and examples in "the climber's fireside book" by Wilfrid Noyce, 1964, Heinemann.
If you don't mean Alpine climbing but do mean pure rock climbng, it could be argued it started in 1881/2 when Walter Parry Hackett Smith did a climb at Wasdale Head in the Lakes District. See "The First Tigers" by Alan Hankinson, 1972, Dent & Sons, ISBN 0 460 03943 1

Roger Caffin

To sum it all up though I had to pretty much agree with this answer...

In his book Downward Bound Warren Harding attempted to answer this question and concluded that it probably had something to do with cavemen fleeing from sabertoothed lions.
Which is as good an answer as any, I think.

--K