Ahmad ibn Muhammad ibn Hanbal (Imam of Ahl al-Sunnah)

Traveling across Iraq, Syria, Yemen, and the Hijaz on foot to collect authentic prophetic traditions, Ibn Hanbal compiled the monumental Musnad containing over thirty thousand hadiths. Under Caliph Al-Ma'mun, when the Mu'tazilite doctrine of the createdness of the Quran was enforced, he stood resolute.

Despite severe torture under successive caliphs, he refused retaliation, preaching patience and forgiveness. His massive funeral procession in Baghdad in 855 CE was attended by nearly a million mourners, cementing his status as the champion of orthodox traditionalism.