In this work the author discusses the concept of the concerto grosso genre associated with the Roman musical environment as it has been represented in the specialist studies written over the last thirty years. Thanks to the close examination of specific aspects connected with the transmission of the music in the 17th/18th-century Roman milieu, and above all in connection with the division of the orchestra into parts for concertino and concerto grosso, there has been a growing tendency to reserve the expression concerto grosso for the music of Roman provenance performed by a concertino and concerto grosso (or at least transmitted with that division) and to adopt the concept of concerto grosso for a genre or performance style specifically associated with the Roman milieu, hence in a sense that is narrower than that encountered in the late-18th-century theoretical literature of Germanic provenance. By examining the peculiar features of the Roman orchestral repertoire of the early 18th-century and endeavouring to establish whether common characteristics of transmission (terminology, appearance in editions) are also accompanied by substantial affinities in compositional terms, this study demonstrates the un-historical nature of using the term concerto grosso to indicate a genre based on a style of orchestration used in this repertoire. At the same time it makes a significant contribution towards retracing the history and developments of Italian instrumental music in the 17th-18th centuries.