Gnosticism (from Ancient Greek γνωστικός (gnōstikós) 'having knowledge'; Koine Greek: [ɣnostiˈkos]) is a collection of different religious and philosophical ideas and systems that fully developed by the mid-2nd century 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.