In the late 1800s, the city of Bia?ystok?"which was once Polish, then Prussian, then Russian and is today again part of Poland?"was a hub of diversity, with large numbers of Poles, Germans, Russians and Yiddish-speaking Ashkenazi Jews. Each group spoke a different language and viewed members of the other communities with suspicion. For years, L.L. Zamenhof?"a Jewish man from Bia?ystok who had trained as a doctor in Moscow?"dreamed of a way for diverse groups of people to communicate easily and peacefully.