In Islamic law the world was made up of the House of Islam and the House of War with the Ottoman Sultan — the perceived successor to the Caliphs — supreme ruler of the Islamic world. However, Suraiya Faroqhi demonstrates that there was no iron curtain between the Ottoman and other worlds but rather a long-established network of diplomatic, financial, cultural and religious connections. These extended to the empires of Asia and the modern states of Europe. Faroqhi's book is based on a huge study of original and early modern sources, including diplomatic records, travel and geographical writing, as well as personal accounts.