This charge they committed to prelates chosen from all nations, who, when the catalogue had been completed, referred it for sanction and approval to the Pope.

He nominated a congregation of eminent ecclesiastics, by whose care the catalogue was perfected, and rules were framed, defining the use that should be made of it in future.

It issued officially, as I have already stated, in 1564, the fifth year of the pontificate of Pius IV., with warning to all universities and civil and ecclesiastical authorities that any person of what grade or condition soever, whether clerk or layman, who should read or possess one or more of the proscribed volumes, would be accounted _ipso jure_ excommunicate, and liable to prosecution by the Inquisition on a charge of heresy.[120] Booksellers, printers, merchants, and custom-house officials received admonition that the threat of excommunication and prosecution concerned them specially.
[Footnote 120: Paulus Manutius Aldus printed this Index at Venice in 1564.] The first rules deal with the acknowledged writings of Protestant heresiarchs.

Those of Luther, Zwingli, and Calvin, whether in their original languages or translated, are condemned absolutely and without exception.

Next follow regulations for securing the monopoly of the Vulgate, considered as the sole authorized version of the Holy Scriptures.