Introduction This chapter focuses on the historical development of the Commission’s External Service: the Commission delegations and their line management, the ‘Relex family’ (the Commission’s directorates-general for development, foreign policy and humanitarian aid in Brussels). The contention of the chapter is that while today’s European External Action Service owes much of its new diplomatic mind-set and its ‘interstitial role’ (Batora 2013) to an innovative fusion of several epistemic communities with distinct diverse mind-sets (Spence 2012), it is based, however, on extrapolation of a previous system of delegations; the Commission’s own ‘External Service’. The Commission’s growing responsibilities for external affairs over the 60 years of the existence of its external activities began with offices in countries where the European Community needed information policy (e.g. Washington) and a management focus for its major development and technical assistance spending programmes. The Commission’s subsequent long experience in external relations was to propel it into a catalytic role during reflections on Europe’s would-be diplomatic service, both during the Convention and in the subsequent negotiations for the Constitutional Treaty and the later Lisbon Treaty. The Commission ‘model’ of a post-Westphalian style European diplomatic service in fact prefigured the post-Westphalian diplomatic model later embodied in the EEAS. By the time of the Lisbon Treaty, some 50 years after the opening of its first delegation outside the European Community, the Commission’s External Service (ES) had become a well-rooted system of EU representation abroad, arguably already fit for purpose as an ‘EU Foreign Service’ (Carta 2012). To set the scene for the analyses in this book this chapter describes the evolution of the Commission’s ‘External Service’ before Lisbon. It posits the idea of a process involving Commission officials first as project managers, but later gradually assuming a diplomatic mantle. The result, when Lisbon later added member state diplomats to the staff, was to be a fusion of foreign, military and development policy responsibilities in today’s EEAS, differentiating the EEAS from the institutional arrangements of the Westphalian state model, where such staff and their ministries would have been separate and nation-state based.