A typed message, with the signature of the physicist and dated June 1951, was addressed to students at Colégio Anchieta in Porto Alegre in the south of the country.
Written in German, it read: “He who knows the happiness of understanding has gained an infallible friend for life. Thinking is to man what flying is to birds. Don’t follow the example of a chicken when you could be a lark.”
The note was authenticated by a legal expert and graphologist, who matched the signature against officially accepted examples of Einstein’s autograph, local media reported.
The school said the letter was sent to the Jesuit institution at the request of father Gaspar Dutra, who lived in the US and met Einstein in New York. Father Dutra later brought the letter to Porto Alegre and kept it locked in the school safe.