Former Egyptian President Anwar al-Sadat shakes hands with former Israeli Premier Menachem Begin as former US President Jimmy Carter looks on, September 6, 1978 at Camp David.(KARL SCHUMACHER/AFP/Getty Images)

Samuel M. Lewis, the longest-serving U.S. ambassador to Israel, died Monday at 83, JTA reports. Lewis served as ambassador to Israel from 1977 to 1985, under Presidents Carter and Reagan, and was a key figure in brokering the 1978 Camp David peace agreement between Israel and Egypt.

Lewis, who wasn’t Jewish, earned the nickname Shmuel Levi from former Israeli defense minister Ezer Weizman due to his interest in Israeli culture and his involvement in communications between the U.S. and Israel.

Israeli President Shimon Peres once said of Lewis, “To say Samuel Lewis is to say champion of peace.”

Lewis, a longtime advocate for a two-state solution, was involved with J Street and the Israel Policy Forum, where he served as a senior policy adviser. Though he ruffled some right-wing feathers over the years, his legacy in the Israel-Palestinian peace process can be seen in the statement released by AIPAC regarding his death. The pro-Israel lobbying organization called Lewis a “dedicated public servant, deeply committed to the peaceful resolution of conflict throughout the world.”

Lewis is survived by his wife and children.