Zamenhof Day Zamenhof Day Zamenhof Day (), also called Esperanto Book Day, is celebrated on 15 December, the birthday of Esperanto creator L. L. Zamenhof. It is the most widely celebrated day in Esperanto culture. On this day, Esperantists hold information sessions and cultural gatherings to promote literature in Esperanto. The history of celebrating Esperanto on Zamenhof's birthday can be traced back to 17 December 1878, when at a birthday party for his 19th birthday he presented to his friends his "Lingwe uniwersala", the first version of his international language. By 1887, this language had evolved into what is now recognized as
Ludwik Birkenmajer w przekładzie polskim" (1920) · Mikołaj Kopernik, "O obrotach ciał niebieskich i inne pisma" (2004) · Andrzej Śródka, "Uczeni polscy XIX-XX stulecia". Warszawa 1994, vol. I, p. 155-157 . Paweł Tarasiewicz, Zbigniew Pańpuch, "Birkenmajer Ludwik Antoni", "Powszechna encyklopedia filozofii" vol. I, Lublin 2000 · Władysław Horbacki, "Ludwik Antoni Birkenmajer (1855-1929)". Łódź 1930 Ludwik Birkenmajer Ludwik Antoni Birkenmajer (18 May 1855 - 20 November 1929), Polish historian of science, physicist, astronomer, professor of the Jagiellonian University. Descended from the German family settled in Galicia (Southern Poland) during the time of the Napoleon wars, later a part of the Austrian Habsburg Empire.