Qusai grew up treating his step-father, Rabi'ah, as his father. When a quarrel broke out between Qusai and some members of the tribe of Rabi'ah, they reproached him and betrayed the fact that they never regarded him as one of their own. Qusai complained to his mother, who replied "O my son," she said, "your descent is nobler than theirs, you are the son of Kilab ibn Murrah, and your people live in the proximity of the Holy House in Mecca." Because of this, Qusai departed from Syria and returned to Mecca.
Life in Mecca
When Qusai came of age, Hulail ibn Hubshiyyah the chief of Banu Khuza'a tribe was the trustee and guardian of the Ka'bah. Soon Qusai asked for and married Hulail's daughter Hubbah. When his father-in-law died after a battle which ended in arbitration, he committed the keys of the Kaaba to Hubbah. Hulail preferred Qusai as his successor from his own sons and according to Hulail's will, Qusai got the trusteeship of the Kaaba after him. Qusai brought his nearest of kin of Quraysh, and settled them in the Meccan valley besides the Sanctuary – his brother Zuhrah, his uncle Taym ibn Murrah, the son of another uncle Makhzum ibn Yaqaza, and his other cousins Jumah and Sahm, who were less close. These and their posterity were known as Quraysh al-Biṭāḥ, whereas his more remote kinsmen settled in the ravines of the surrounding hills and in the countryside beyond and were known as Quraysh aẓ-Ẓawāhir. Qusai ruled as a King. He reconstructed the Kaaba from a state of decay, and made the Arab people build their houses around it. He is known to have built the first "town hall" in the Arabian Peninsula, a spacious dwelling which was known as the House of Assembly. Leaders of different clans met in this hall to discuss their social, commercial, cultural and political problems. Qusai created laws so that pilgrims who went to Mecca were supplied with food and water, which was paid for by a tax that the people paid. He distributed the responsibilities of looking after the visitors during pilgrimage, taking care of the Kaaba, warfare, and pacifying amongst myriad tribes living in Mecca.
Sons
Qusai had many sons, some of them being Abd, Abd-al-Dar, Abd Manaf and Abd-al-Uzza. It was a marked characteristic of Qusai's line that in each generation there would be one man who was altogether pre-eminent. Among his four sons, Abd Manaf was already honoured in his lifetime. However Qusai preferred his first born, Abd-al-Dar, although he was the least capable of all so he singled out Abd Manaf his second son for his honor and presrige. Shortly before Qusai's death he invested all his rights, powers, and transferred the ownership of the House of Assembly to Abd Manaf.
Descendants
The following Royal and Imperial dynasties claim descent from Qusai:
