Papal legates have attracted much scholarly interest. Studies usually focus on legal aspects and on the practice of the fully developed type of papal representation since the times of church reform and the Investiture Contest. Rennie, however, aims at clarifying the fundamental developments of this institution. He bridges the gap between the ancient imperial legatus and the time of Pope Gregory vii, taking into consideration all documents available (p. 16). The book starts with concepts and theories (chs i–ii), then points out the pivotal points of development (chs iii–iv). The requirements needed to become a papal legate and the practice of the office are investigated (chs v–vi), while special attention is paid to councils as an arena of papal representation and its representatives (ch. vii). Two chapters deal with the intensification in the eighth and ninth century and, at last, the ‘new era’ (ch. ix) of legatine action that began with Gregory vii, when the office of papal legate reached its maturity and legates became, to quote once more from Petrus Damiani, ‘the eyes of the pope’. Rennie employs the term ‘legate’ in a broader sense, since the sources examined use a range of terms for papal representatives (for example apocrisiarius, vicarius, nuntius, defensor ecclesiae) rather than a clear-cut terminology. Guided by the idea that developing forms of representation reflect both the increasing significance of the Roman Church and a significant need for ecclesiastical leadership in its distant regions, he identifies stages of development. First, the mid fifth-century popes, with Leo i being to the fore, employed the tools of the Roman emperors to stabilise their view of an expanding Church under the control of the Roman bishop. Next, the author posits standardisation from the middle of the eighth century because of papal orientation towards the Franks as the new political power in Europe. Here, the archetypes of papal officials were created that would bring papal authority to every region of Christendom. Whereas earlier papal officials normally acted as legati ad causam, legatine authority now began to correspond with certain reigns, regions or ecclesiastical provinces. By concentrating on contemporary expectations and perceptions, aims and effects Kriston Rennie draws a finely nuanced picture. This small but thorough book is most welcome as a way to throw light on papal legates avant la lettre.