35 Chalkidike was the main region of Athonite landownership from the foundation of the great monasteries of Lavra and Iviron in the late tenth century to the end of Byzantine rule of the peninsula in 1423. he aim of this paper is to examine the evolution of the possessions of the monks in Chalkidike and to consider the impact of the Holy Mountain on the economy and settlement in the peninsula. he exploration of this topic is based on the medieval documents preserved in the archives of Athos, which concern the properties the monasteries owned in Chalkidike, the lower Strymon valley and certain other regions. Beyond the economy and settlement, the Athonites and their dependencies exercised an important inluence on many other spheres of life in Chalkidike, including the ideology and the culture of the local population, but this unfortunately remains largely obscure. he settlement and economy in Macedonia and especially in Chalkidike were the main ields of enquiry of Jacques Lefort, one of the principal editors of the Athonite documents. hanks to his close study of these texts as well as to local inspection, the Parisian scholar has more than anyone else advanced our understanding of these matters. In the Dumbarton Oaks Spring Symposium of 1987, dedicated to Mount Athos, Lefort gave a paper entitled Le rôle du Mont Athos dans le développement économique de la Macédoine, a topic that is obviously very close to ours. his paper has apparently remained unpublished. Apart from Lefort, several other scholars have examined the agrarian economy, the settlement and the role of the great landowners, primarily on the basis of the Athonite documents. Contrary to previous studies that use these sources in order to study the Byzantine economy and landlords in general, here we focus on the impact of a distinct group of landowners, the great Athonite monasteries, on a speciic region, Chalkidike. Ater some remarks on the monasteries as landowners, we will explore the evolution of Athonite landholding in the peninsula. We will conclude with a preliminary assessment of the signiicance Kostis Smyrlis, Guentcho Banev and Giorgos Konstantinidis Mount Athos and the economy of Chalkidike, tenth to iteenth century