This thesis discusses the sources of royal power in the kingdoms of Argead Makedonia and early Ptolemaic Egypt. The overarching aim is to assess the degree of change and continuity between the structures and networks that framed Argead and Ptolemaic royal power. Viewing power not as an abstraction but as the outcome of the real and observable interrelations between individuals and groups, this thesis builds upon the historical sociology of Michael Mann in order to identify four main sources of royal power: dynastic, courtly, military and economic. In their capacity to enhance or limit royal power, the social networks that are formed between the king and representatives of these groups in each context, as well as the structures that produce and reproduce their behaviour, form the focal points of this research. As such, this thesis distances itself from that segment of socio-historical tradition, which grants ultimate primacy to human agency. The Introduction presents the main scholarly debates surrounding the nature of Ptolemaic and Argead kingship and highlights the fact that although both have received considerable attention separately, they have not yet been the focus of a systematic, comparative analysis. At the same time, this chapter brings in the theoretical and methodological framework employed in the thesis. Chapter One discusses the structural organisation of the dynasty, focusing on patterns of marriage and succession, and the manipulation of dynastic connections, real or constructed, as instruments of legitimation. It is argued that the colonial circumstances in early Ptolemaic Egypt led to an amplification of the importance of the dynasty as a source of power. Chapter Two examines the interrelations of the ruler with his extended circle of friends and associates, i.e. the courtiers. A discussion of the physical and social structure of the courts in Aigai, Pella and Alexandria in the early Ptolemaic period confirms that administration at the highest level continued to be organised around personal relations. Chapter Three identifies the enabling mechanisms, which sustained the military power of the Makedonian king. It is argued that royal military leadership and the integration of facets of military organisation (e.g. the institution of klerouchia) and values (through education) in society remained integral to the social organisation of early Ptolemaic Egypt. Finally, Chapter Four examines the economic power of the ruler, as revealed by the organisation of property rights. The absence of the Makedones and the prominence of temples as economically significant groups in early Ptolemaic Egypt underline the structural discontinuities that arise from the necessary adaptation to different local conditions. This thesis concludes that the structures that framed Argead royal power were in their majority remembered and instantiated in the organisational practices of the early Ptolemaic rulers. Deviations from the Argead paradigm occurred when pragmatism led to the introduction of corrective practices, such as the co-regency principle aimed at eradicating the dynastic instability that had plagued the Argead monarchy, and when ecological and political considerations, such as the needs of their non-Hellenic, non-Makedonian audience, dictated a greater degree of accommodation to local conditions, especially in the field of economic organisation. Even there, however, one can discern the influence of the flexible, all-inclusive model of Argead administration of its New Lands as an organisational template.