There is little information in the early Muslim sources about Mu'awiya's rule in Syria, the center of his caliphate. He established his court in Damascus and moved the caliphal treasury there from Kufa. He relied on his Syrian tribal soldiery, numbering about 100,000 men, increasing their pay at the expense of the Iraqi garrisons; also about 100,000 soldiers combined.

Mu'awiya is credited by the early Muslim sources for establishing diwans (government departments) for correspondences (rasa'il), chancellery (khatam) and the postal route (barid). According to al-Tabari, following an assassination attempt by the Kharijite al-Burak ibn Abd Allah on Mu'awiya while he was praying in the mosque of Damascus in 661, Mu'awiya established a caliphal haras (personal guard) and shurta (select troops) and the maqsura (reserved area) within mosques.