Prophet Muhammad (PBUH) was born into the polytheistic society of the Arabian Peninsula but refrained from idol worship. At the age of forty, he was appointed as a prophet, with his primary message being the call to monotheism. He described the purpose of his mission as the completion of noble morals. The polytheists of Mecca persecuted him and his followers for years, yet they remained steadfast in Islam. For thirteen years, the Prophet (PBUH) called the people of Mecca to Islam, and later migrated to Medina — an event that became the beginning of the Islamic calendar.