Abd al-Malik was the fifth Umayyad caliph, ruling from 685 to 705 CE. He is known for consolidating the Umayyad dynasty's power and implementing significant administrative reforms. His reign marked the establishment of Arabic as the official language of the empire, which helped unify the diverse regions under Umayyad control. One of his notable achievements was the construction of the Dome of the Rock in Jerusalem, a significant Islamic architectural landmark. Abd al-Malik also introduced a new currency, which facilitated trade and strengthened the economy. His leadership played a crucial role in shaping the early Islamic state.