The sanctuary of a Catholic church symbolizes Heaven. It is the sacred space, the sanctum sanctorum, where Our Lord in the Blessed Sacrament is reserved and where the Sacrifice of the Mass takes place. It is for these reasons that it is richly embellished. It has to stand out from the rest of the church. The apse, the ceiling of the sanctuary above the altar, even more poignantly calls to mind the heavenly Jerusalem. In the ancient basilicas of Rome, it is common to see vibrant gold mosaics coat the apse. At the Basilica of Santa Maria in Trastevere, Christ and His Mother are enthroned in royal Byzantine attire. Christ is affectionately shown with his arm around his mother, who appears as an empress.

Santa Maria in Trastevere, source:

Blue is another color that calls to mind our eternal home. In sacred art, from Eastern iconography to Renaissance masters, blue is traditionally linked to the divine nature of Christ, whereas red points to his human nature.

This is the newly restored apse at Saint Stanislaus in Milwaukee. Note the celestial blue and regal gold. The eyes look up and heaven is artistically made present. Two angels with gold thuribles bow reverently before the Lamb of God, who stands on the Book of Revelation with its seven seals. The Ten Commandments are underneath the closed book. This is a full circle snapshot of salvation history: Old and New Testament, Christ as “the Beginning and the End.” Early church martyrs, holding palm branches, are set against golden backdrops as if floating in the sky, while the Holy Spirit, in the form of a dove, hovers in the middle.