Muslim armies conquered territory in the first century of Islam, as empires did in that age, but conquest and conversion are different. Most people in the conquered lands became Muslim gradually over centuries, and the world's largest Muslim country, Indonesia, was reached by traders and teachers, not by an army.
The Quran forbids forcing people into religion. In Egypt, Syria and Iraq, Muslims remained a minority for several centuries after the conquests, and Christian, Jewish and Zoroastrian communities survived and flourished under Muslim rule. If the conversions had been forced, there would be no Christians left in the Middle East. Islam spread in Southeast Asia, West Africa and East Africa mainly through merchants, scholars and Sufi teachers.
Islam was and is also the fastest-growing major religion in several countries today, where there is no army. Still, historians acknowledge that there was political pressure in some times and places, such as higher taxes for non-Muslims. The question is how far the rulers' conduct reflects the religion, and in Muslim teaching, forced conversion is invalid.
لَآ إِكْرَاهَ فِى ٱلدِّينِ ۖ قَد تَّبَيَّنَ ٱلرُّشْدُ مِنَ ٱلْغَىِّ ۚ فَمَن يَكْفُرْ بِٱلطَّٰغُوتِ وَيُؤْمِنۢ بِٱللَّهِ فَقَدِ ٱسْتَمْسَكَ بِٱلْعُرْوَةِ ٱلْوُثْقَىٰ لَا ٱنفِصَامَ لَهَا ۗ وَٱللَّهُ سَمِيعٌ عَلِيمٌ ﴿٢٥٦﴾
There shall be no compulsion in [acceptance of] the religion. The right course has become clear from the wrong. So whoever disbelieves in Taghut and believes in Allah has grasped the most trustworthy handhold with no break in it. And Allah is Hearing and Knowing.
وَلَوْ شَآءَ رَبُّكَ لَءَامَنَ مَن فِى ٱلْأَرْضِ كُلُّهُمْ جَمِيعًا ۚ أَفَأَنتَ تُكْرِهُ ٱلنَّاسَ حَتَّىٰ يَكُونُوا۟ مُؤْمِنِينَ ﴿٩٩﴾
And had your Lord willed, those on earth would have believed - all of them entirely. Then, [O Muhammad], would you compel the people in order that they become believers?
This answer follows the mainstream Sunni understanding and is general learning, not a fatwa. Where Muslims differ, the answer says so. Have a question of your own? Write to us.
