The Hijra was the migration in 622 AD of Muhammad and his followers to Medina, <u>to escape the polytheist persecution that was plotting to kill </u><u>Muhammad </u><u>in </u><u>Mecca</u>.
In Medina he had a secure position and was able to craft the Constitution of Medina in wich <u>he united the arabic tribes</u>, some of wich had already converted to his preachings of Islam, establishing the basis of a multi-religious Islamic state, and at the head of their armies conquered Mecca, <u>establishing the </u><u>foothold </u><u>of what would by </u><u>750 </u><u>had become the </u><u>Umayyad Islamic Caliphate</u><u>, extending from Spain to India</u>.
The Industrial Revolution changed material production, wealth, labor patterns and population distribution. Population movement was caused by people living in small farming communities who moved to cities. These prospective workers were looking for wage labor in newly developed factories.