Dhia' ul-Dīn 'Abd al-Malik ibn Yūsuf al-Juwaynī al-Shafi'ī (Persian: امام الحرمین ضیاءالدین عبدالملک ابن یوسف جوینی شافعی, 17 February 1028 – 20 August 1085;[4] 419–478 AH) was a Persian[5] Sunni scholar famous for being the foremost leading jurisconsult, legal theoretician and Islamic theologian of his time.
In addition to learning fiqh and usul al-fiqh from his father, Imam al-Haramayn received some legal instruction from the leaders of the Shafi'is in Marw, al-Qadi Abu ali Husayn b. Muhammad b. Ahmad al-Marw al-Rudhi, and al-Qasim al-Furani.
[13] Al-Juwayni was left to flee Nishapur by force when the Karramite governor Al-Kundduri passed a verdict to curse Abu Hassan al-Ashari during the weekly Friday prayer gatherings and to imprison any of his adherents.
[14] His scholarship was so widely acclaimed amongst the scholars of the Hejaz that he acquired the title of Imam al Haramayn meaning "leading master of the two holy cities".
He gained a large following and was invited back to Nishapur as an undisputed grand mufti once Nizam Al Mulk took power, and was appointed the headmaster of newly built prestigious Nizamiyya school where he stayed for the next 30 years, training and preparing for the next generation of Shafi'i jurists and Ash'ari theologians.
[11] Al-Juwayni spent his life studying and producing influential treatises in Muslim government; it is suspected that most of his works (below) came out of this period after his return from Mecca and Medina.
(By this al-Juwanyni meant, your books outshine me)[20]He died of liver disease and was buried at his home after a huge crowd attended his funeral.
"[21] Al-Juwayni, a Sunni jurist and Mutakallim, or scholar engaged in the study of theological principles, spent his life deciphering between what a Muslim ought and ought not to do.
"[11] Al-Bakhirzi made a comparison of Al-Juwanyi's to Al-Shafi'i and Al-Muzani in jurisprudence, Al-Asmaʿi in manners, Al-Hasan al-Basri in preaching eloquence, and Al-Ash'ari in speculative theology.
"[11] His well-known works: The book Fara'id al-Simtayn is sometimes mistakenly thought to be authored by the Sunni Abd'al Malik al-Juwayni.