This paper elaborates the gist of professional collegia. Generally speaking, the colleges were voluntary associations that brought together members based on common activities, depending on their professional or sacral characteristics. The principal difference between the two groups was that the sacral groups were gathered around a cult, while the professional groups were occupied with craftsman activities. The members of the colleges were often libertines, whose aspiration to enter such associations was initiated by their eagerness to elevate their social status. Regardless of their personal status, colleges were considered the golden middle of the Roman social structure - the, so called, plebs medium. Their origin often presented a barrier to the entrance among elite. Therefore, their main objective was to accumulate as much capital and power as possible, which would ultimately provide them with an excellent platform for integration among the elite. The sole purpose of this paper is to explain who were colleges (what status they had in society and how these associations influenced the Roman world), and to provide an overview of their impact in Dalmatia province.