The Middle Ages were already under way when Islam began to spread in Arabia. It spread to Persia and Palestine. Then it spread into India, across North Africa, into other parts of Africa, to Asia Minor, to Central Asia, Southeast Asia, to Spain, Sicily, Southern Italy, the Balkans, the Philippines, and Indonesia. There is a link below.
Answer 1because it was a better thing that more people knew what Islam wasAnswer 2While trade was certainly good for the spread of Islam, there is no clear information that shows that the spread of Islam had a positive influence on trade. The trade routes under Islam were no different than the previous trade routes except for the religion of the merchants. Perhaps higher quantities of merchandise were moved since people naturally trust people with their own religious faith all else equal, but there is insufficient information to show this.
The golden period of Islam was most likely the rule of the early Ummayad and Abbasid Caliphs, whereupon most of the islamic middle east was united under a single ruler. Under the early Sunni Abbasid caliphs, in particular the Caliph Harun al-Rashid, science and art flourished, in a time where Islamic culture vastly surpassed western European society (which still dwelled in the dark ages). The Golden age of islam can best be seen as the time period between 750 AD- 1258 AD, brought to an end by, not so much the Crusades but more the Mongol invasion, the death of the last Caliph and the gradual political fragmentation of the Islamic world.
There is a problem in that this question assumes that "Islam", a religion/concept/ideology, etc. can have its own agency. "Islam" is only extant at the will of its believers, so we can answer how Islam made it to Africa, but assert no existential reason "why Africa was chosen" or something similar, since Islam did no choosing. Islam was first brought to Africa (Egypt specifically) by the Islamic conquests under the Rightly-Guided Caliphate. The successor Umayyad Caliphate conquered all of North Africa from 640-680 C.E. and brought the religion with them as they conquered. In some areas, especially the urban centers, conversion to Islam occurred rapidly (100-200 years) but in the rural areas, conversion was generally slower. There were only a few attempts in the first 300 years of Islam in North Africa to convert people to Islam by force. As for Sub-Saharan Africa, Islam was originally brought and spread by Arab and Amazigh traders from North Africa. Their educated nature and good disposition led to the peaceful conversion of the African civilization of Ghana to Islam and the founding of the Islamic Mali Empire and Songhai Empire. In the Horn of Africa and Sudan, Christianity were relatively firmly planted. However, Muslims began to make in-roads by forming naval city-states in Somalia, Kenya, and Tanzania. The Egyptian conquest of Sudan several centuries later led to the conversion of the north Sudanese to Islam.
Palestine was first conquered by Muslims led by General Khalid al-Waleed under the banner of Caliph Omar in 634 C.E. With the exception of about a century of the Crusader Kingdoms, Palestine was under Islamic control until 1919 C.E. when it came under British control. Once Palestine was controlled by Muslims, who used discriminatory practices to promote Islam, large sections of the population converted.
The political centre of Islam was Damascuss under the Umayyad Caliphate.
Because it was the age of enormous importance to the development of world knowledge and technology. It came in a time when Islam and the People of the Book living under the nation of Islam were politically united and lived in harmony. As usually said, our unity has always lead to our strength and on the other hand fitnais the source of our weakness. The golden age of Islam brought about wonders to the world whether scientific, educational, architectural, medical and or any other subject one can think of.
The Abbasids were the Muslims, neither Christians nor Jews. Many Muslim families have been ruling the Muslims.
The Rashidun Caliphate under Omar.
The Umayyad Caliphate conquered much of what is Pakistan today in the early 700s. Under the Umayyads, Islam became the state religion in those areas it controlled. Islam expanded to central and eastern India during the reign of the Islamic Mughal Empire in the 1500s.
From 1210 AD. to 1288 in the golden age of Islam under the caliphate of alghazali and the reign of Sultan Al-Adil Sayf Al-Deen
In 762 AD, the Abbasid Caliphate under Al Mansur built a new capital at Baghdad.
There is no concept of a monarchy in Islam. There are "Muslim" countries today that have a king, but such kingship and handing down of power and authority from one generation to the next within the family is not allowed at all under Islam. Instead they have something called a Caliphate, where people choose a Caliph (a leader).
Trade flourished under the Abbasids at first because they moved the capital of the Muslim empire to the newly created city of Baghdad in central Iraq in 762. The city was located on key trade routes that gave the caliph access to trade gold, good, and information about.
It's really hard to find accurate demographic information from so long ago, as even today not all places keep records of religious affiliation. However, at the peak of Rashidun Caliphate in 654 AD, about 40 million people or 19 percent of the world's population lived under Muslim rule. Most of these people became Muslim, as they were either Arabs who had come with the invading Arab armies or the progeny of these invaders, or they were forced to convert to Islam, or religious persecution under Islamic rule convinced them to convert to Islam. So we can say that less than 19% of the world in 654 AD was Muslim. Under the Ummayad Caliphate from 661-750 this increased, through further Muslim conquests, to 62 million people or nearly 29% of the world's population. Under the Abbasid Caliphate, which began in 750 and continued until 1517 when it fell to the Ottomans, the Muslims experienced a golden age and there was increased Arabization throughout the Caliphate. We can conclude an even larger percentage of people became Muslim throughout the empire at this time. At its demographic zenith in 850 AD, 50 million people lived in the Abbasid Caliphate or roughly 20% of the world's population. The majority were Muslim. So... we can estimate that somewhere in the neighborhood of 50 million Muslims were living around 1000 AD, and they made up about 20% of the world's population. Which is the same percentage they make up today. Hmm... for being the world's "fastest growing religion," it sure has not grown much in the last 1162 years... and actually, compared to the percentages in the 7th Century, Islam has shrunk.
There are two questions. Let's answer them in turn.How did the Mongols expand their empire through warfare?The Mongols were very skilled in the art of war, especially cavalry movements. Mongols, by nature of their society in the Steppes, had become avid horsemen and were knowledgeable concerning battle since they often had fights with one another. When Genghis Khan was able to unite all of the Mongols under one banner, the amount of equipped Mongols was immense.Light cavalry (which was the dominant Mongol attack force) easily routed armies by outmaneuvering them on the open plains and violently massacring all who opposed them. This increased the fear of non-Mongols of the Mongol advance and made them more willing to surrender. With the exception of the Ismailis in Iran and the Mamluks in modern Israel, they suffered no major loss and the Ismailis were later defeated anyway.How did the Abbasid Caliphate expand using religion?The Abbassid Caliphate did not expand their empire through religion. The Abbassid Caliphate fought several wars to maintain their borders and even enslaved Turkish boys to fight their wars for them. (These slaves were called the Mamluks and they eventually rose up against the Abbassids and created their own empires.)The Abbassid Caliphate helped to expand the religion of Islam both through unequal policies towards non-Muslims (which can be read about in the Related Question below) and by engaging in trade and diplomatic missions to distant countries. These missions spread the concepts and beliefs of Islam to other countries.
There are two "Islams". The first is the religion which spread primarily through peaceful interaction or the benefits it provided under the stewardship of an Islamic State. The second Islam was an actual Empire or Islamic State which expanded through warfare and conquest. It is necessary to understand that while the Islamic Empire grew through warfare, most conversions to Islam were not compelled.