Under the influence of this idea, the Blessed Sacrament in the processions which became common after the institution of the feast of Corpus Christi in 1246, came by degrees to be carried in transparent vessels, resembling our present monstrances. Moreover, a custom grew up, especially in Germany, of keeping the Blessed Sacrament continually exposed to view in churches. It was forbidden by many synods, but a sort of compromise was arrived at through the construction of the Sakramentshauschen of which so many examples still exist in central Europe. These tabernacles, of great height and imposing appearance, were erected in the most conspicuous part of the church, and there the Blessed Sacrament was reserved in a monstrance behind a metal door of lattice-work which allowed a more or less free view of the interior. It was thus that the practice developed, though partly kept in check by synodal decrees, of adding solemnity to any function, even the Mass itself, by exposing the Blessed Sacrament during its continuance.