The Lateran is the oldest established Basilica, built by the command of Constantine soon after the legalization of Christianity. Constantine gave the ancient palace of the Laterani family to Pope Miltiades. Pope Sylvester dedicated the basilica around 324 as Most Holy Savior; only after the 6th century were the names of St. John the Baptist and St. John the Evangelist used.
While many home churches existed before that time this marks the beginning of something special, and reflects the many churches throughout the world from small to large, open wooden structures to massive stone edifices.
The beauty and harmony of the churches, destined to give praise to God, also draws us human beings, limited and sinful, to convert to form a “cosmos,” a well-ordered structure, in intimate communion with Jesus, who is the true Saint of saints. This happens in a culminating way in the Eucharistic liturgy, in which the “ecclesia,” that is, the community of the baptized, come together in a unified way to listen to the Word of God and nourish themselves with the Body and Blood of Christ. From these two tables the Church of living stones is built up in truth and charity and is internally formed by the Holy Spirit transforming herself into what she receives, conforming herself more and more to the Lord Jesus Christ. She herself, if she lives in sincere and fraternal unity, in this way becomes the spiritual sacrifice pleasing to God.
Dear friends, today’s feast celebrates a mystery that is always relevant: God’s desire to build a spiritual temple in the world, a community that worships him in spirit and truth (cf. John 4:23-24). But this observance also reminds us of the importance of the material buildings in which the community gathers to celebrate the praises of God. Every community therefore has the duty to take special care of its own sacred buildings, which are a precious religious and historical patrimony. For this we call upon the intercession of Mary Most Holy, that she help us to become, like her, the “house of God,” living temple of his love.
— Benedict XVI, Angelus Address, November 9, 2008