An emin was an officer in the Ottoman empire; a "steward", the holder of an eminet, and often responsible for customs duties.
[2] The emin was usually a customs officer - that is to say, a gümrük emini ; they were responsible for managing revenue from certain taxes, and collected duties on goods exported by foreigners.
Although formally a tax official, the role of the emin (as with the role of other officials, such as the Kadi) could vary in practice; they might also be involved in consular, mediation, or even notarial work; and as a representative of the Ottoman state, could be authorised to apprehend Ottoman subjects who had committed crimes on foreign territory.
As such, an emin resident in a foreign port that traded with the Ottoman empire could be valuable to both parties.
The emin might also be appointed to project-manage major construction work, and would submit a full report on each project - with financial details.