It is not so common to find that a Christian place of worship – almost covering the whole of heaven – is dedicated to “ALL SAINTS”, usually it is one (or occasionally two) named saints who are the patron saints of a church – and thus usually over the municipality or town in which it is located.
But to search for the origin one has to go far back in history, because a pagan custom can be seen as a model for this practice of dedicating to ALL SAINTS, according to which there were already central temples in pre-Christian times, which were dedicated to all deities (PANTHEON) were consecrated. Possibly the most famous Pantheon, once a pagan temple and now a Christian place of worship, is in the Italian capital.