In 1816 in Civita Lavigna (Lanuvium), some local farmers unearthed dozens of fragments of an inscription which was to become the most important primary source for several generations of historians studying Roman private associations. After all the fragments had been reassembled, it turned out that the inscription was a list of by-laws of an association which referred to itself as the collegium salutatre Dianae et Antinoi. The text fell into the hands of Theodor Mommsen and became the impulse for writing his famous treatise De collegiis et sodaliciis Romanorum. Mommsen, son of a Lutheran minister and an apostate at the same time, having analysed the ‘statute’ of the Lanuvian cultores Dianae et Antinoi, concluded that the ‘true’ purpose of such associations was to ensure decent burial for their members. In this way, the German scholar equated the concepts of collegia funeraticia and collegia deorum. The religious aspect of the functioning of these organisations was so thoroughly eliminated from the scholarly discourse by Mommsen’s collegia funeraticia that even in the early 21st century many historians were surprised by the assertion that associations of cultores did indeed have clearly religious functions. This study is an attempt to move cultic collegia out of the shadow of Mommsen’s funeral associations and to return them to the role of an independent subject of research, which will enable scholars to answer questions about their organisation and social composition, and most importantly to reveal their multi-functional character.