“The Feast of the Cross had its origin at Jerusalem, and is connected with the commemoration of the Finding of the Cross and the building, by Constantine, of churches upon the sites of the Holy Sepulchre and Calvary. In 335 the dedication of these churches was celebrated with great solemnity by the bishops who had assisted at the Council of Tyre, and a great number of other bishops. This dedication took place on the 13th and 14th of September.
This feast of the dedication, which was known by the name of the Encaenia, was most solemn; it was on an equal footing with those of the Epiphany and Easter. The feast of the Exaltation of the Cross sprang into existence at Rome at the end of the seventh century. The Gallican churches (i.e. those in France), had another on the 3rd of May of the same signification. The date seems to have been borrowed from the legend of the Finding of the Holy Cross (Lib. Pontif., I, p. cviii). Later, when the Gallican and Roman Liturgies were combined, a distinct character was given to each feast, so as to avoid sacrificing either. The 3rd of May was called the feast of the Invention of the Cross, and it commemorated in a special manner Saint Helena's discovery of the sacred wood of the Cross; the 14th of September, the feast of the Exaltation of the Cross, commemorated above all the circumstances in which Heraclius recovered from the Persians the True Cross, which they had carried off. Nevertheless, it appears from the history of the two feasts, which we have just examined, that that of the 13th and 14th of September is the older, and that the commemoration of the Finding of the Cross was at first combined with it.” The Catholic Encyclopaedia.
This feast displaces the liturgical texts for 24th Sunday of Ordinary Time. In the red Parish Mass books the texts are on p.191. NB. There will be no Mass this Thursday due to a meeting.