Lazaro Luiz Zamenhof (or Ludwik Lejzer Zamenhof) was born on 15 December 1859 in Bialystok, Poland. He was the son of Rosalia and Mark Zamenhof, a perceptive teacher of geography and modern languages. The story of the boy Lazarus' life, the town where he was born and the historical moment are crucial in triggering some reflections that would culminate in the creation of Esperanto.

Bialystok, then annexed to the Russian Empire, was a town torn apart by political, religious and linguistic differences; four languages were spoken there: Polish, Yiddish, Russian and German, and the boy Lazarus witnessed arguments and disputes that often ended in tears, blood and even violent deaths. This terrible impression would never fade from his mind, so from childhood he cherished the dream of creating a language through which the inhabitants of his town and the whole world could understand each other.

He learned several languages (in addition to the four languages of his hometown): Latin, Hebrew, French, Greek and Italian, among others. In 1878 he wrote "Lingve Universala", which was to become the predecessor of Esperanto.

Zamenhof's family moved to Warsaw and, after finishing school, he was sent to Moscow to study medicine. While he was away, his father, worried about his son's future, burned his manuscripts on the International Language.

On returning to his father's house and realising what had happened, Lazarus patiently began to reconstruct his entire project. Only after exhaustive experiments and meticulous testing of the grammar and vocabulary, which he had intensively experimented with and tested, did he consider his work ready. He translated into Esperanto great works of world literature, among them the Bible (Old Testament) and Shakespeare's Hamlet. He was then 28 years old.

On 26 July 1887, with the financial support of his future father-in-law, Zamenhof launched Esperanto into the world with a small grammar in Russian, "Lingvo Internacia", written by "Doktoro Esperanto" (a pseudonym which, in the new language, means "doctor who has hope"). Eventually, the pseudonym came to be used for the language itself: Esperanto.

Without leaving his profession, as an ophthalmologist, Lazarus worked hard to make the International Language known. It was only after he had finished and published his work that he decided to marry. On 9 August 1887 he married Klara Silbernik, with whom he had three children: Lidia, Adam and Sophia.

In August 1905, Zamenhof saw his ideal come true at the First Universal Esperanto Congress in Boulogne-sur-Mer, France, where hundreds of people from different countries gathered to communicate in a single language during the six days of the event. The creator of the Language of Fraternity also attended eight other universal congresses, giving speeches at almost all of them, always travelling on his own, with difficulties, but never taking advantage of his prestige.

In 1914, the outbreak of World War I interrupted the spread of Esperanto for a time. Shaken and suffering from heart problems, Zamenhof died three years later, on 14 April 1917, in Warsaw, Poland.

Lazaro Luiz Zamenhof was a man endowed with extraordinary willpower to spread his humanist ideal. He was a true universalist, pacifist and thinker who fought against sectarianism. His life was woven of sacrifices, self-denial and devotion; he was an extremely sympathetic man, who cultivated tolerance and kindness towards all, never missing an opportunity to be charitable. For this, UNESCO recognised him with merit as a "benefactor of humanity", a spirit who bequeathed to the human family the ideal instrument for communication between its members and for its progress based on universal brotherhood.