Louis-Christophe Zaleski-Zamenhof as not only the first such World Congress in the third millennium of the civil calendar but also the third century of Esperanto, reminding the delegates: "You came to discuss intercultural dialogue, the pressing need for which inspired the initiation of the international language. In fact, almost all his biographies relate the story of the young Ludwik Łazarz Zamenhof living in the multicultural city of Białystok, observing the animosity that then governed relations among the varied nationalities, not finding a commonly understandable language, a tool that was, as he said, necessary for dialogue among the respective cultures. Mutual dialogue enables
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 &