Gnosticism is a collection of religious and philosophical ideas and systems that coalesced in the late first century AD among sects of early Christianity and other faiths. It is not a singular, homogeneous tradition or religion, but an umbrella term used by modern scholars to describe different groups and beliefs that shared certain characteristics. These diverse Gnostic groups generally emphasized personal spiritual knowledge (gnosis) above the authority, traditions, and proto-orthodox teachings of organized religious institutions. The Gnostic worldview typically distinguished between a hidden, uncorrupted supreme being and a flawed demiurge responsible for creating material reality. Gnostics held this material existence to be evil and believed the principal element of salvation was direct knowledge of the supreme divinity, attained via mystical or esoteric insight. Many Gnostic texts deal not in concepts of sin and repentance, but with illusion and enlightenment.