How were Christians and Jews treated under the early Muslim Empire?

Answer 1

Non Muslims were paying an extra part (to balance more or less the taxes paid by Muslims as 'Zakat' or Alms giving according to their second pillar of the Islam five pillars). On the other hand this extra tax was paid by only non Muslims who are entitled for military service but exempted from doing it (for this reason, it was not to be paid by old citizens, women, children, physically potent citizens, ... etc).

Currently both Muslims and non Muslims; in any Muslim country; are paying same taxes and accordingly practicing equal citizenship social, political, economical. and military service duties.

Answer 2

As 'people of the Book', there was generally no explicit compulsion on Christians and Jews to convert to Islam, as there was for pagans in the early years of Islam. However, they were treated as second-class citizens and forced to pay heavy taxes that did not apply to Muslims. When the time came for payment of the tax, some rulers made this as humiliating as possible.

If Christians and Muslims were unable to pay the poll tax, they would be forced to give up children, to be brought up as Muslims. In spite of this, Islam treated Christians better than Christians would later treat Muslims.