This paper proposes a new explanation of the intriguing distribution pattern of peak sanctuaries in Crete during the MM period, and the reasons for their fast expansion in the late Proto-Palatial period, followed by a sudden decline soon afterwards. The working hypothesis presented here is based on my intensive fieldwork carried out during the last decade and is supported by several recently identified sites which shed new light on these problems. At present about 40 sites in Crete can be classified as peak sanctuaries. They are mostly grouped in three regions: central Crete, the East Siteia peninsula and the Rethymnon isthmus, with a few “anomalous” sites beyond these regions. It is indisputable that the earliest, the most important and the longest-lived peak sanctuary was Iouchtas, closely related to Knossos. Iouchtas became a model-site, the idea of which spread to other parts of the island. Some regions, however, as for example those controlled by Malia and Phaistos, showed strong resistance to it. It will be argued in this paper that the peak sanctuary on Iouchtas did not reflect a universal idea of a mountain deity shared by all Cretans, but rather represented a local Knossian concept of a holy mountain which later became the sanctuary of a young storm-god (?), the protector of Knossos. The distribution of peak sanctuaries may thus represent the territorial and/or ideological expansion of Knossos during the MM IB and MM II periods and not the popularity of a mountain deity in Crete. The abandonment of most of the peak sanctuaries, at the end of the MM IIB or in the MM III period, was caused neither by natural disasters, nor by changes in religious concepts at the beginning of the Neo-Palatial period, but was a simple result of their intentionally short-lived, extraordinary function.