L. L. Zamenhof the Yiddish form of the forename and a russified version of his surname; many later Russian language documents also include the patronymic "Markovich", as is the custom in the language. His family name is of German origin and was originally written "Samenhof"; the spelling Zamenhof reflects the romanization of the Yiddish spelling , as well as the Esperanto and Polish spellings. In his adolescence he used both the Yiddish "Leyzer" and the Russian "Lazar". While at university, Zamenhof began using the Russian name "Lyudovik" (also transcribed "Ludovic" or translated as "Ludwig") in place of "Lazar", possibly in honor of Francis
Ludwik Birkenmajer of scholars. He was married Zofia (Sophie), the daughter of Franciszek Karliński, the professor of astronomy in the Jagiellonian University, and inherited his library embracing mostly the books on mathematics and physics. They had three sons: Aleksander Ludwik (historian of culture and exact sciences, and bibliologist), Józef (poet, interpreter and literature historian), and Wincenty (Polish philologist, teacher and renown Tatra Mountains-climber). His grandson is Krzysztof Birkenmajer (professor of geology, member of the Polish Academy of Sciences). In 2011 the Institute for the History of Science of the Polish Academy of Sciences received the name of father and son: Ludwik &