Hi Joe,

You can mouse over the letters in the graphic below to find out what they mean; the English translation follows the picture of St. Peter's.

Stretching across the facade is the dedicatory inscription:

IN HONOREM PRINCIPIS APOST PAVLVS V BVRGHESIVS ROMANVS PONT MAX AN MDCXII PONT VII

translated into English:

In honor of the prince of Apostles; Paul V Borghese, Pope, in the year 1612 and
the seventh year of his pontificate.

I hope this helps,

Mike