Embassy of the United States to the Holy See to the Holy See, previously located on Aventine Hill, moved to new headquarters in September 2015 in a separate building on the same compound as the United States Embassy Rome. Embassy of the United States to the Holy See The Embassy of the United States of America to the Holy See (or Embassy Vatican for short) is the diplomatic mission of United States of America to the Holy See, a term referring to the central government and universal reach of the Roman Catholic Church. The current embassy moved to new headquarters in September 2015 in a separate building on the
Foreign relations of the Holy See Holy See, not to Vatican City State. It is the Holy See that establishes treaties and concordats with other sovereign entities and likewise, generally, it is the Holy See that participates in international organizations, with the exception of those dealing with technical matters of clearly territorial character, such as: Under the terms of the Lateran Treaty, the Holy See has extraterritorial authority over various sites in Rome and two Italian sites outside of Rome, including the Pontifical Palace at Castel Gandolfo. The same authority is extended under international law over the Apostolic Nunciature of the Holy See in a foreign