The discovery of the early bronze age sanctuary on the Cycladic island of Keros is briefly described. Why islanders in the Aegean should establish the world's first maritime sanctuary around 2500 bc is then considered, and other instances of early centres of congregation are briefly discussed. Specific features of the Special Deposit South at Kavos, a key component of the sanctuary, are then reviewed along with those of the accompanying settlement on the islet of Dhaskalio. The Aegean context for the development in the later bronze age of cult, involving the reverence of specific deities, is then surveyed. The conclusion is reached that the Confederacy of Keros may not have involved the practice of cult in this sense, but rather the perform ance of rituals of congregation such as are widely seen at very early centres before the development of hierarchically ordered ('state') societies.