Ludwig Lazarus Zamenhof
Ludwik Lejzer Zamenhof (15 December 1859 – 14 April 1917), often credited as L. L. Zamenhof, was a Jewish eye physician and the inventor of the international language Esperanto, the most widely-used constructed language.
He was a Zionist, but later rejected all forms of nationalism.
He supposed that the main reason for conflicts lay in mutual misunderstanding caused by the lack of a common language. If such a language existed, Zamenhof postulated, it could play the role of a neutral communication tool between people of different ethnic and linguistic backgrounds.