Einstein would not call himself a mathematician:-)
"Historically well-known" is an ill defined description. It depends on place and time.
Until 18s century only one language was necessary to do mathematics: Latin.
Euler wrote in German, French and Latin (mathematics in Latin, other things
in French and German). He lived and worked in Russia for a large part of his life, but the sources I know do not tell whether he spoke Russian:-)
Newton wrote mathematics in Latin, other things in English.
Proceedings of St Petersburg Academy founded in 1740-th had two official languages: Latin for mathematics and French for all other sciences.
Latin was a part of any high school and university curriculum in Europe until late 19s century.
Until the middle of 20s century most mathematicians could read mathematics in German, French and English. (Mathematical papers were rarely, almost never translated. And a serious mathematician had to be aware of the literature in his area. This was not possible without working knowledge of these three languages)).
When I first met my future adviser (in 1971) he asked what languages I can read.
I was a first year student, and I replied with some pride: English and French.
He was not impressed and told me: a mathematician has to read in ALL languages:-) So we are returning to the situation which existed at the times
Knowledge of foreign languages declined in the second half of 20s century: English gradually displaced other languages in mathematics, and at this time a mathematician can survive if s/he knows only English.