In the Baháʼí writings Muhammad is known by the titles the Apostle of God, the Seal of the Prophets and the Day-Star of Truth. Writing of Muhammad, ʻAbdu'l-Bahá states that through God's aid, he was able to unite the warring tribes of the Arabian Peninsula 'to such an extent that one thousand tribes were welded into one tribe'. This, he writes, despite the fact that he (Muhammad) was an illiterate man born into a cruel and barbarous culture. He was nevertheless responsible for producing 'a book in which, in a perfect and eloquent style, He explained the divine attributes and perfections, the prophethood of the Messengers of God, the divine laws, and some scientific facts.ʼ Abdu'l-Baha believed that one of the proofs that the Qurʼan is a product of the divine are the facts about the workings of nature contained therein, facts which he believed were not known in Muhammad's own time. He claimed, for example, that Sura 36 of the Qurʼan depicts a heliocentric understanding of the solar system.