Hassan ibn Thabit was a great and a known Arab poet. He was hired by the Quraish leadership of Makkah to prepare a masterpiece to spread propaganda against the Last Messenger of God, Muhammad (peace be upon him).
Hassan thought that he should go and see this men in order to write his poem. When he saw the face of Prophet Muhammad, he accepted Islam, went back returned the money & wrote a poem (below) about the physical characteristics of Prophet Muhammad. After that he became the official poet of the Prophet and became the defender of the Prophet and of Islam against the propaganda by the people of Quraish.