The general historiography of Stuart diplomacy has, by and large, argued that those who were tasked with carrying out foreign policy were ineffective, amateurish and, in some cases, incompetent. This harsh view is in need of reassessment in the light of a number of incidents, which suggest that much effective foreign policy and general diplomatic work was carried out by lower-ranking diplomats, who were titled agents. These agents have attracted little historical comment or study. This thesis sets out to redress this by considering the agents employed from 1603 to 1688, when the title disappeared due to rank inflation, duties transferred to consuls, and other factors. The texts of the period on the perfect ambassador leave clear omissions in descriptions of diplomatic work, which therefore suggests a role for another type of diplomat, the agent. The initial chapter looks at background and education and offers a portrait of an average agent as typically a well-educated member of the lower gentry. The terms under which agents served are compared with other professional groups of comparable social rank and those in other government positions. Agents’ work in information gathering, including where and from what sources they obtained material and how it was transmitted, is investigated. The existence of an efficient international network is uncovered. Agents’ role in negotiations, unconstrained by protocol, allowed them a greater degree of freedom than ambassadors. This and the element of deniability are key to understanding their importance to Stuart diplomacy. The task of protecting merchants’ rights is demonstrated by a case study in France which shows all the usual stages involved in resolving a dispute. Involvement in buying naval supplies and cultural transfer are also discussed in chapters concerned with agents’ practical activities. Finally, the careers pursued after their agencies are outlined, showing how some, such as Cottington, used their skills and knowledge to their advantage. Having demonstrated the differences amongst, and the utility of, agents it is possible to suggest that some of the criticism of Stuart diplomacy comes from a misunderstanding of the use of both agents and ambassadors, and how, when and why each could be employed for a specific task.