It is common wisdom that the ideology of multiculturalism was invented after WWII in the USA and exported from there to Europe. Norwegian blogger Fjordman over at the "Gates of Vienna" is of a somewhat different opinion. According to him, elements of such ideology can be traced in the works of marxist theoreticians like Antonio Gramsci and Georg Lukács.
However, cultural relativism, as basis for multiculturalism is far older then that and Fjordman has been able to find traces of that even in the works of Voltaire and Edward Gibbon. In an uncanny resemblance to modern-day multiculturalists Voltaire even sings praises to Islam and debases Judaism and Christianity.
It would be interesting to know whether Voltaire and Gibbon ever read the Koran and the Hadith. Nonetheless, these two were restricted in terms of information flow and travel means of their time. What's the excuse of contemporary multiculturalists?