Its uses were confined to a belief in religious inspiration, or to intense religious fervour or emotion. Thus a Syrian sect of the 4th century was known as the Enthusiasts. They believed that by perpetual prayer, ascetic practices and contemplation, man could become inspired by the Holy Spirit, in spite of the ruling evil spirit, which the fall had given to him. From their belief in the efficacy of prayer, they were also known as Euchites. Several Protestant sects of the 16th and 17th centuries were called enthusiastic. During the years immediately following the Glorious Revolution, "enthusiasm" was a British pejorative term for advocacy of any political or religious cause in public. Such "enthusiasm" was seen in the time around 1700 as the cause of the previous century's English Civil War and its attendant atrocities, and thus it was an absolute social sin to remind others of the war by engaging in enthusiasm. The Royal Society bylaws stipulated that any person discussing religion or politics at a Society meeting was to be summarily ejected for being an "enthusiast." During the 18th century, popular Methodists such as John Wesley or George Whitefield were accused of blind enthusiasm (i.e. fanaticism).
Science-fiction writer Thomas M. Disch once suggested that the mystical experiences of writer Philip K. Dick might be described as a form of enthousiasmos.
The Enthusiast also refers to the "Type Seven" personality type (not to be confused with the "Type Three"/"Type A" personality) . People who fall into this modern definition of "Enthusiasts" are adventurous, constantly busy with many activities with all the energy and enthusiasm of the Puer Aeternus (Peter Pan Complex). At their best they embrace life for its varied joys and wonders and truly live in the moment but, at their worst, they dash frantically from one new experience to another, too scared of disappointment to actually enjoy themselves. Enthusiasts fear being unable to provide for themselves or to experience life in all of its richness.