God is a deity in theist and deist religions and other belief systems, representing either the sole deity in monotheism, or a principal deity in polytheism. God is most often conceived of as the supernatural creator and overseer of the universe. Theologians have ascribed a variety of attributes to the many different conceptions of God. The most common among these include omniscience, omnipotence, omnipresence, omnibenevolence (perfect goodness), divine simplicity, jealousy, and eternal and necessary existence. God has also been conceived as being incorporeal, a personal being, the source of all moral obligation, and the "greatest conceivable existent". These attributes were all supported to varying degrees by the early Jewish, Christian and Muslim theologian philosophers, including Maimonides, Augustine of Hippo, and Al-Ghazali, respectively. Many notable medieval philosophers developed arguments for the existence of God, attempting to wrestle with the apparent contradictions implied by many of these attributes.