Which Umayyad ruler standardized the currency?

Abdul Malik ibn Marwan is widely recognized for standardizing the currency of the Umayyad Caliphate. He introduced the first purely Islamic coinage, replacing the Byzantine and Sasanian coins previously in circulation. These new coins, dinars (gold) and dirhams (silver), bore Arabic inscriptions and Islamic symbols, establishing an independent Islamic economic identity.

• Umar bin Abdul Aziz (Umar II) was known for his piety and just rule, not primarily currency standardization.
• Marwan II was the last Umayyad caliph.
• Al-Walid I was Abdul Malik's son, known for building projects, but the currency reform was his father's achievement.