Battle of Tabouk
The Battle of Tabouk (also called the Battle of Tabuk) was a military expedition, which, according to Muslim biographies, was initiated by Muhammad in October, AD 630. Muhammad led a force of as many as 30,000 north to Tabouk in present-day northwestern Saudi Arabia, with the intention of engaging the Byzantine army. Though not a battle in the typical sense, if historical the event would represent the opening conflict in the coming Arab–Byzantine wars. There is no contemporary Byzantine account of the events, and much of the details come from later Muslim sources. Noting this, as well as the fact that the armies never met, some Western scholars have questioned the authenticity of the details surrounding the event; though in the Arab world it is widely held as historical.
Reasons for war
According to Ar-Rahīq al-Makhtum, a modern Islamic biography of Muhammad written by the Indian Muslim author Safiur Rahman Mubarakpuri, the reason for war against the Byzantine Empire, was that one of Muhammad's ambassadors was killed by Sharhabeel bin ‘Amr Al-Ghassani (the governor of Al-Balqa). This immediately led to the Battle of Mutah. But Mubarakpuri also claims that event was one of the reasons of the Battle of Tabouk also. Mubarakpuri further mentions that the emperor of the Byzantine Empire, Heraclius was preparing a force to demolish the growing Muslim power in the region.