Among the seven fuqahaa (jurists) who formulated the fiqh of Medina in the time of the Tabi‘in and one of Muslim historian.
He was considered an authority on the early history of Islam. It is uncertain whether he wrote a book, but there are many traditions that have been handed down in his name by Ibn Ishaq, Ibn Sa'd, and al-Tabari. For this reason he is often referred to as the founder of Islamic history.
He was born in the khalifate of 'Uthman ibn 'Affan and died in 94 AH. He lived through the seditions which occurred after the murder of 'Uthman until authority was settled with the Marwanids. Although his brother, 'Abdullah ibn az-Zubayr, wrested the rule from 'Abdu'l-Malik ibn Marwan, and the conflict became intense between them, it is not known that he became involved in the business or helped his brother in any way. It is clear that he completely devoted himself to study, studying fiqh and hadith. In hadith he was, as his student Ibn Shihab said, "a sea undiminished by buckets." Ibn al-Musayyab had the most fiqh of the Tabi'un in Madina. 'Urwa had the most hadiths. He learned the fiqh of the deen from a group of the Companions, particularly 'A'isha, the Mother of the Faithful. She was foremost in general knowledge, rules for the apportionment of shares of inheritance and rulings. Al-Qasim ibn Muhammad, the son of her brother, took knowledge from her as did 'Urwa, the son of her sister Asma'. 'Urwa was the person with the greatest knowledge of the hadiths of 'A'isha. He said, "Before 'A'isha died, I saw that I had become one of four authorities. I said, 'If she dies, there will be no hadith which will be lost from those she knows. I have memorized all of them."
It is clear that 'Urwa was concerned with recording the fiqh and hadith he learned and it is related that he wrote books; but he was afraid that they might become books alongside the Book of Allah and so he destroyed them. His son Hisham related that he had books which he burned on the day of the Battle of Harra. He later he regretted that, however, and used to say, "I would rather have them in my possession than my family and property twice over."
http://www.islamweb.net/newlibrary/showalam.php?ids=16561