Thanks to my daily companion, In Conversation with God, (in volume 7) I was able to understand this feast!
It explains that The basilica of St. John Lateran was one of the first churches built by Christians following the early persecutions. It was raised in Rome under the Emperor Constantine and s the first Western church to have the invocation of the Saviour. The Lateran Basilica was consecrated by Pope Sylvester on this day in the year 324.
Originally celebrated in Rome, the feast became universal in the Roman Rite as a sign of unity with the Holy See. This church continues to be the Cathedral of the Roman Pontiff to this day. Its long history evokes memories of the many thousands of people who have received Baptism within its ancient walls.
Keep a look out!