The Romans used the Latin word fanum meaning "sacred precinct" for other cult sites that did not contain a temple, such as the early sacred site of the grove of Diana Nemorensis ("Diana of Nemi") and 'temples' of divinities other than those traditionally revered by their native paganism, the state religion.
Like the corresponding Latin adjective, fanaticus, the modern word fanatic still reflects the disapproval by pious traditional Romans of various exotic religious practices. Nevertheless under the Roman Empire some of the imported cults, mainly from conquered people, such as the PersianMithras and Ancient Egyptian divinities such as the mother-goddess Isis and Serapis (for his fanum the specific term serapeum was used) would gain great popularity, demonstrated in rich temple cults. The temple of Isis and Serapis in the Campus Martius, built of Egyptian materials and in the Egyptian style to house the Hellenized cult of the Egyptian deity Isis, is typical of the heterogeneity of later Roman religious monuments.
The word became part of several Roman place names, notably Fanum Voltumnae (possibly Viterbo or Montefiascone), Fanum Martis Famars or Fanum Fortunae (modern Fano)
They would only be virtually wiped out together with the Roman paganism after early Christianity and Christianity was officially adopted by the Roman Empire. The word temple would be transferred to its churches, as well as synagogues; occasionally fanum was also used as such, e.g. Fanum S. Andreae for Santander.