The high degree of specialisation achieved in the Roman world covered a vast area of trades and reached beyond economy and production into specialised knowledge and science, but in the transition to the Middle Ages large parts of this knowledge were lost. The continuity and end of some specialised trades which were common in the early Empire but which were rare (or disappeared) in late Antiquity can be seen through the material and written record. In this paper, we aim to explain the divergent evolution of two such professions (medics and engineers) in the western provinces, adding more examples and further case-studies to current debates. Whereas medics and medicine continued as a profession, in part through the protection of the Church, specialised engineers and architects (which were usually linked to state training and employment) seem to have disappeared, together with the state structures that supported them