merits. He had old canals dug and new ones opened. He built a new capital — Wasit — midway between Kufah and Basrah. He introduced regulations to reform currency, taxes and measures. He is credited, perhaps wrongly, with introducing orthographical signs into the Koran to indicate vowel sounds and to distinguish between similar-appearing consonants in order to prevent incorrect reading of the sacred text. Justifiable or not, the repressive measures he took restored order in Kufah and Basrah, hotbeds of dis- content and opposition. The state authority was likewise firmly established along the eastern coast of Arabia, including hitherto independent Oman. His viceroyalty also embraced Persia, where his forces practically eliminated the most dangerous Kharijite sect and even penetrated into India. His success depended upon the faithful support of his Syrian troops, in whom his confidence — like his loyalty to the Umayyad house — knew no bounds.
During the reigns of Abd-al-Malik (685-705) and his four sons the Umayyad dynasty in Damascus reached the meridian of its power and glory. The Islamic empire attained its greatest expansion, from the shores of the Atlantic and the Pyrenees to the Indus and the confines of China — an extent greater than that of the Roman empire at its height. At no time before or after did the Arabs control so large a territory. It was during this period that the definitive subjugation of Transoxiana, the reconquest and pacification of North Africa and the acquisition of the Iberian peninsula were accomplished. To this era also belong the Arabicization of the state administration, the introduction of the first purely Arab coinage, the develop- ment of a system of postal service and the erection of such architectural monuments as the Dome of the Rock in Jerusalem, the holiest sanctuary in Islam after those of Mecca and Medina.
Syria's severance from the Byzantine empire considerably reduced its maritime trade, but that was somewhat
