Chehlum or Arbaeen (Arbayeen) in Arabic means "forty", is a Shia religious observation that occurs 40 days after the Day of Ashura (Aashura/Ashurah), the commemoration of the martyrdom by beheading of Imam Husayn Ibn Ali (the grandson of the Prophet Muhammad) which falls on the 20th day of the second month of the Islamic Lunar Calendar (Safar).
The 40th [Arbaeen or Chehlum] marks an important turning point in the movement of Karbala (Kerbala). This day, which is no less important to the day of Ashura (Aashura/Ashurah) is important for many reasons - the prime being that the Ahlul Bayt reached the land of Karbala on this day and performed the visitation to Sayyid ash-Shuhada al-Husayn and the loyal family and friends who gave their life for the cause of Islam.
