The Cycladic island of Tinos is the centre of one of the most important Orthodox pilgrimages in Greece, but also of a Catholic pilgrimage, which attracts Catholic devotees from all over the country. The more pious inhabitants of Tinos are actively involved in their parishes ; an important number of locals own private chapels, which are spaces of cult that the Church does not strictly control. Some of these devotional practices have an obligatory character, while others are transgressive, since they pertain to interactions between confessional groups, going beyond the institutional limits. This article shows how the concept of “capital of sacredness” allows to think these different devotional expressions as a resource that social agents can manipulate.