The former president of the UN Special Tribunal for Lebanon (STL), Italian jurist Antonio Cassese, died Saturday in Florence, dpa reported.
The cause of death was cancer, Italian media reported.
Italian President Giorgio Napolitano said in a statement that Cassese was "a jurist of high prestige in the field of international law and a protagonist of the International Criminal Court."
Foreign Minister Franco Frattini echoed Napolitano's statement, eulogizing Cassese as "an enlightened mind, a brave man and a solid and precious point of reference."
Cassese had been working on the case to try suspects in the 2005 assassination of former Lebanese Premier Rafik Hariri, but resigned, citing health concerns, on October 10 and returned to Italy.
Cassese was the first president of the International Criminal Tribunal for the former Yugoslavia (ICTY), a position which he held from 1993 to 1997.
David Baragwanath has been named Cassese's replacement as president of the Lebanon tribunal and presiding judge of its appeals chamber.
Cassese was born in 1937, in Atripalda.