Tafsir is one of the earliest academic activities of Muslims. According to the Quran, Muhammad was the first person who described the meanings of verses for early Muslims. Other early exegetes included a few Companions of Muhammad, like ʻAli ibn Abi Talib, ʻAbdullah ibn Abbas, ʻAbdullah ibn Umar and Ubayy ibn Kaʻb. Exegesis in those days was confined to the explanation of literary aspects of the verse, the background of its revelation and, occasionally, interpretation of one verse with the help of the other. If the verse was about a historical event, then sometimes a few traditions (hadith) of Muhammad were narrated to make its meaning clear.