“There is a wealth of source material concernig Gotama Buddha, far more than for (Confucius or Jesus Christ, for example. The problem thus becomes one of selection. There are also, as Erich Frauwallner has pointed out, far more historical facts available for the Buddha than for his near contemporaries, the Greeks Thales and Pythagoras. There can be no doubt concerning the cxistence of the person who advocated the unique thought that we attribute to him.”
Book:Gotama Buddha