Some of the oldest Early Christian basilicas were four that were begun in Rome by the Emperor Constantine. Three of them are still standing, but they have had many changes in the last 1,700 years. These are the basilicas of "Santa Maria Maggiore", "St. John Lateran" and "St. Paul's outside the Walls". The fourth basilica was "'Old St. Peter's" which was replaced in the 16th and 17th centuries by the present St. Peter's Basilica. Other Early Christian Basilicas were built in Greece and the Holy Land.