The Nobel physics laureate who developed the theory of relativity was born in the southwestern German city of Ulm on March 14, 1879.

Hugely popular despite the complexity of his subject, he came to symbolize eccentric genius thanks in part to an iconic image of a tousle-haired Einstein sticking his tongue out.

In a ceremony in Ulm, Rau said Einstein had set ethical guidelines for all scientists to follow by "engagement for the human good".

He hailed his "almost childlike wonderment" and "unblinkered thinking".

Although he was born in Ulm, Einstein's family moved to Munich in southern Germany when he was just six weeks old.

He was educated there, in Italy and Switzerland before returning to Germany but emigrated to the United States in 1933 as Hitler was taking power.

A national survey on German ZDF public television last year found him only 10th in a list of all-time German greats, well behind the likes of religious leader Martin Luther and writer Johann Wolfgang Goethe.AFP