The First to Dedicate A Space for a Mosque
Sufiyan relates a narration from his father that Hazrat Ammar (ra) was the first person who dedicated the space in his house to be used as a mosque for worship.
(At-Tabaqat Al-Kubra, Vol. 3, p. 189, Ammar bin Yasir, Dar-ul-Ihya At-turath Al-Arabi, 1990, Beirut)