Ibelin was a castle in the Crusader Kingdom of Jerusalem in the 12th century (at modern Yavne, 31°49′12″N 34°42′47″E / 31.820°N 34.713°E / 31.820; 34.713), which gave its name to an important family of nobles.
Read more about Ibelin: The Castle, First and Second Family Generations, 13th Century, Lords of Ibelin, Family Tree