The 'Islamic world' was not a single state in the Middle Ages, but the different countries which formed it had many things in common:
It was united – the Umma was the community of all Muslim believers and shared a commitment to Islam.
Religion and government were much more closely connected in the Muslim states than in feudal Europe. The ulama, the experts in Sharia law, were important religious scholars who advised the caliph, the leader of the umma. Until the 9th century the caliph was the religious and political leader of all Muslims. Later on, military leaders, known as amirs or sultans, dominated the caliphs, but the caliphs kept their spiritual role.
The Islamic world - a larger and more advanced civilisation
It was created by the Arab conquests of the 7th and 8th centuries.
From the 11th to the 16th centuries many thousands of Turks and Mongols migrated across the vast plains of Central Asia into the Middle East. They also adopted Islam.
It stretched from India to Spain.
Muslim traders travelled to places as far apart as the Sahara, South Africa, China, Scandinavia and Russia.
Muslims traded high-quality goods such as silk, carpets, ivory and spices.
Knowledge of science and medicine in the Islamic world was far more sophisticated than in Western Europe.
Cordoba in Muslim Spain was a city of over half a million inhabitants with street lighting and running water. At the same time 10,000 Londoners lived in timber-framed houses and used the river as their sewer.
Muslims were going to beauty parlours, using deodorants and drinking from glasses, at a time when English books of behaviour were still telling page-boys not to pick their nose over their food, spit on the table, or throw uneaten food onto the floor.