But few people know that Islam once adopted these institutions, in a period of history scholars refer to as 'the Golden Age', which remarkably coincided with the Dark Ages. Well, most historians understand the Islamic Golden Age as a period of history under the Abbasid Dynasty, which ruled from the 8th to the 13th century. At that time, Islam was only a century old and concentrated in the Arabian Peninsula, the Mediterranean, and North Africa. Once the Abbasids took over and formed a caliphate, the capital was moved to Baghdad and Islam spread to other regions. One of the most unique characteristics of the Islamic Golden Age was its inclusiveness. Many scholars of the Golden Age put their studies into practice, particularly in the fields of medicine and health. In the 10th century, pharmacies were a staple in most Muslim cities and hospitals were open 24 hours. The golden age also saw the foundation of Sufism, which is a mystical Islamic philosophy that promotes peace, education, and philanthropy. Millions of people still adhere to Sufism, and the practice has been promoted as an alternative to radical forms of Islam. Most historians mark the 13th century as the end of the Golden Age, when Genghis Khan and his Mongol army conquered much of East Asia, including the Islamic Caliphate. If the story had developed differently, it is not known what Islam would be like today.