The Imāms `Alī l-Hādī (also known as "an-Naqī") and Hassan al-`Askarī lived under house arrest in the part of Samarra that had been Caliph al-Mu'tasim's military camp ("`Askaru l-Mu'tasim"). As a result, they are known as the "`Askariyyān" ("Dwellers in the Camp"). They died and were buried in their house on Abī Ahmad Street near the mosque built by Mu'tasim. A later tradition attributes their deaths to poison.