Since the end of the second century, the cult of the virgin Thecla (the liturgical solemnity falls on 24 September), who did not hesitate to shed her blood for Christ the Lord, has been witnessed. Many churches have been built in her honour: the ancient Cathedral of Milan was dedicated to her.
The great bishop Ambrose repeatedly proposed Thecla as a model of faith and constant perseverance in her love of the Saviour to the consecrated virgins. The name of this Martyr has been inscribed in the Eucharist Canon of the Milanese liturgy since ancient times.
In Duomo, at the beginning of the Holy Chapter Mass, during the solemnity of the holy martyr Thecla, Patron Saint of the Cathedrals’ Parish, one of the most evocative rites of the Ambrosian liturgy takes place: the Rite of the Lighthouse.
This custom most certainly derives from an even older tradition, likely dating back to the seventh century and, in the Milanese context, referring precisely to the Duomo’s liturgy, to at least the twelfth century.
The rite characterised certain celebrations of particular importance, like when the entrance procession had reached the alter, the pharus was lit, a sort of chandelier formed by a crown of lights above which was placed a ring of cotton wool which, when burned, lit the individual lamps.
The interpretation that scholars give to this ancient rite fluctuates between the purely functional (the rapid lighting of all lamps at once) to the allegorical (image of the triumph and glory of the Martyrs, whose feast days were celebrated with this rite), as well as the idea that the lighting of the lighthouse is an element that simply serves to render particularly solemn the beginning of the liturgical celebrations on special days.
Over time, the lighthouse transformed from a crown of lights to a globe of cotton wool, hung at the entrance to the presbytery, which the celebrant would set fire to using three lighted candles fixed on top of a pole, after the initial procession and traditional song of the 12 Kyrie eleison, before going up to the altar. In this case, the meaning of the rite alludes to the sacrifice made by the Martyrs.