The Rise of the Byzantine Iconoclasts

A History of Mankind (382)

The Islamic failure to conquer Constantinople with troops that included many Christian soldiers unwilling to fight for the Muslims had a massive impact on future policies in the Caliphate.

First, the failure convinced newly ascended Caliph Umar ibn Abd al-Aziz (Umar II), designed as successor by his short-lived predecessor, Sulayman (r. 715-717), to order a withdrawal to the previous borders with Byzantium. Most importantly, it influenced his decision to publish an edict clarifying that all those who would convert to Islam would stop paying jizya, regardless of their ethnicity, and that adult converts wouldn’t be forced to undergo circumcision – a major barrier of entry until then.

Following Umar II’s edict, Islam became the world’s easiest religion to convert to: only a few simple words were needed, with no ritual or learning process involved. And it has remained so to this day.

Now, leaving Islam, that’s another thing altogether.