Abū ʾl-Yaqẓān ʿAmmār ibn Yāsir ibn ʿĀmir ibn Mālik al-ʿAnsī al-Maḏḥiǧī (أبو اليقظان عمار ابن ياسر ابن عامر ابن مالك العنسي المذحجي) also known as Abū ʾl-Yaqẓān ʿAmmār ibn Sumayya (أبو اليقظان عمار ابن سمية) was one of the Muhajirun in the history of Islam and, for his dedicated devotion to Islam's cause, is considered to be one of the closest and most loyal companions of Muhammad and to Muslims; thus, he occupies a position of the highest prominence in Islam. Belonging to the Banu Makhzum tribe, Ammar was born in the year 567 to Yasir ibn Amir and Sumayyah bint Khayyat, both of whom were brutally killed. At an early age, Ammar converted to Islam by the invitation of Abu Bakr, becoming one of the earliest Muslims. He became one of the most prominent companions of Muhammad by participating in all of his military conflicts and battles. Historically, Ammar ibn Yasir was the first Muslim to build a mosque. After the death of Muhammad, Ammar remained loyal to Ali and is referred to by Shia Muslims as one of the Four Companions. Muslims consider Ammar's ultimate fate to be unique among the fates of Muhammad's companions, for they perceive his death at the Battle of Siffin as the decisive distinguisher between the righteous group and the sinful one in the First Fitna. ʿAmmār belonged to Banu Makhzum tribe in Hijaz (current-day Saudi Arabia). He was born in the Year of the Elephant, which was the same year as Muhammad's birth, in Mecca and was one of the intermediaries in Muhammad's marriage to Khadijah bint Khuwaylid. His father, Yasir ibn Amir, was from the tribe of Qahtan in Yemen and migrated to Mecca and settled down there after marrying Sumayyah bint Khayyat, a slave woman; Ammar and his parents, Yasir and Sumayyah, were slaves to Abu Huzaifa, but upon his death, Abu Jahl -who became later one of Islam's most brutal enemies and the infamous torturer of Ammar and his parents- took them over as his slaves. Ammar's trust in and knowledge of Muhammad's credibility, even before his prophethood, encouraged him to follow Muhammad's prophetic visions as one of the earliest converts.