It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that when the Muslims came to Madinah Munawwarah, there was no call to prayer (adhan) at that time, rather people would gather at an estimated time. One day they discussed this matter, and some people said that a bell should be made to inform others, as the Christians do. Some said that a horn should be made like the Jews’ horn. Sayyiduna Umar (may Allah be pleased with him) said,“Why don’t you send a man to announce the prayer?”Upon hearing this, the Noble Prophet (peace and blessings be upon him) said to Sayyiduna Bilal (may Allah be pleased with him):“Bilal, get up and announce the prayer.”