Ahl al-Kisa, or the People of the Cloak, refers to Prophet Muhammad (S.), his daughter Lady Fatima (S.A.), his cousin and son-in-law, Imam Ali, and his grandsons Imam Hasan (A.S.) and Imam Hussain (A.S.). They are also called Panj-Tan in Persian, meaning "The Five".
The origin of the term Ahl al-Kisa stems from the event of the Tradition of the Cloak, or Hadith al-Kisa', a narrative of an incident where Prophet Muhammad (S.) assembled Imam Ali (A.S.), Lady Fatima (S.A.), Imam Hasan (A.S.), and Imam Hussain (A.S.) under his cloak and announced them as his Ahl or Family.
It was then that the second part of verse 33 of Surah al-Ahzab (Qur'an 33) of the Holy Quran was revealed, known as "Ayat al-Tatheer" (Verse of Purificatiton), in which Allah states that He has purified the Ahl al-Bayt (A.S.), the Family of the Prophet, thus proving their infallibility.
Learn more about Hadith al-Kisa here.
