In the spirit of Caliph Omar, who reportedly burned the Library at Alexandria, noting that if the books contradicted the Koran, they were heretical, if they agreed with it, they were superfluous. An interesting point of view: all writings were religious, including Ptolmey, transcriptions of ancient Babylonian astronomical observations, history, poems. No wonder Islam bans music.
Up capturing a city, he was asked what to do with its inhabitants, some Mulsims, some infidels, and he said - wait for it - kill them all, let Allah sort them out.
That's the parallel that came to my mind. Anyone wondering how Islam has changed in the 1300 years since that man-caused disaster will see that the faith has stayed true to its roots. This is very much like the destruction of the Buddhas of Bamiyan:
Before Taliban on left, after Taliban on right.
Would like to see a reference on that one. Omar was in general a fairly human guy as caliphs went.
OTOH, there is a well-attested story of the Crusade against the Cathars of southern France.
"The Béziers army attempted a sortie but was quickly defeated, then pursued by the crusaders back through the gates and into the city. Arnaud, the Cistercian abbot-commander, is supposed to have been asked how to tell Cathars from Catholics. His reply, recalled by Caesar of Heisterbach, a fellow Cistercian, thirty years later was "Caedite eos. Novit enim Dominus qui sunt eius."—"Kill them all, the Lord will recognise His own."
http://en.wikipedia.org/wiki/Catharism
