After Prophet Muhammad settled in Abu Ayyub al-Ansari's home in Medina, he purchased the lot next to it and started building a masjid there. This became known as Al Masjid an-Nabawi (the Prophet's Mosque) and Masjid al-Haram (the Sacred Mosque). Azan was legislated soon after, and within half a year after hijra the Second Pact of Brotherhood was made between the Muhajireen and Ansaar.