The greatest of the Safavid monarchs, Shah Abbas I the Great (1587–1629) came to power in 1587 aged 16. Abbas I first fought the Uzbeks, recapturing Herat and Mashhad in 1598, which had been lost by his predecessor Mohammad Khodabanda by the Ottoman–Safavid War (1578–1590). Then he turned against the Ottomans, the Safavids their archrivals, recapturing Baghdad, eastern Iraq and the Caucasus provinces and beyond Ottoman–Safavid War (1603–1618). Between 1616–1618, following the disobedience of his most loyal Georgians subjects Teimuraz I of Kakheti and Luarsab II of Kartli, Abbas carried out a punitive campaign in his territories of Georgia, devastating Kakheti and Tbilisi and carrying away 130,000 – 200,000 Georgian captives towards mainland Iran. His new army, which had dramatically been improved with the advent of Robert Shirley and his brothers following the Persian embassy to Europe (1599–1602), pitted the first crushing victory over the Safavids archrivals, the Ottomans in the abovementioned 1603–1618 war and would surpass the Ottomans in military strength. He also used his new force to dislodge the Portuguese from Bahrain (1602) and Hormuz Island (1622) with aid of the English navy, in the Persian Gulf.
Question: How many years old was Shah Abbas I the Great when he recaptured Herat and Mashhad?
Answer: 17