Arbaeen means the fortieth day, and 20 Safar, which is forty days after the martyrdom of Imam Hussain (AS) on the day of Ashura, is called Arbaeen Hosseini or Arbaeen Day.

According to historical reports, Jabir bin Abdullah Ansari, a companion of the Prophet of Islam (PBUH), along with Atiya Awfi, on the first fortieth anniversary of the martyrdom of Imam Hussein (AS), appeared as the first pilgrims at the tomb of Imam Hussein (AS) and visited Imam Hussein's grave. is

The survivors of the Karbala incident also returned to Karbala on this day and visited the grave of Imam Hussain (AS) and other martyrs of Karbala.

Moving towards Karbala on the day of Arbaeen has been common among Shiites since the time of Imam Masoom (AS), and Shiites were bound to this movement even during the time of Bani Umayyah and Bani Abbas.

The recommendation for the Arbaeen pilgrimage has caused Shiites, especially the residents of Iraq, to ​​move to Karbala from different parts of the country. This movement, which is often done on foot, is considered one of the most crowded marches in the world. After the fall of the Iraqi Baath party, the number of these pilgrims has multiplied, so that reports have announced the presence of 30 million pilgrims in recent years.