To consolidate Umayyad rule after the Second Fitna, the Marwanids launched a series of centralization, Islamization and Arabization measures. To prevent further rebellions in Iraq, al-Hajjaj founded a permanent Syrian garrison in Wasit, situated between Kufa and Basra, and instituted a more rigorous administration in the province. Power thereafter derived from the Syrian troops, who became Iraq's ruling class, while Iraq's Arab nobility, religious scholars and "mawālī" became their virtual subjects. The surplus from the agriculturally rich Sawad lands was redirected from the "muqātila" to the caliphal treasury in Damascus to pay the Syrian troops in Iraq. The system of military pay established by Umar, which paid stipends to veterans of the earlier Muslim conquests and their descendants, was ended, salaries being restricted to those in active service. The old system was considered a handicap on Abd al-Malik's executive authority and financial ability to reward loyalists in the army. Thus, a professional army was established during Abd al-Malik's reign whose salaries derived from tax proceeds.