Khandaq refers to a significant event in early Islamic history, specifically the Battle of the Trench, which took place in 627 CE. This battle was a defensive strategy employed by the Muslims of Medina against a coalition of tribes, including the Quraysh. The Muslims, led by the Prophet Muhammad, dug a trench around the city to protect themselves from the attacking forces. The trench was inspired by the advice of Salman the Persian, who suggested this tactic based on his experiences. The battle ended in a stalemate, with the coalition unable to breach the defenses, ultimately leading to their withdrawal and a significant victory for the Muslims.