Eleven different editions of the Index in my own possession prove this.

Nearly all of these declare on their title-pages that they are issued by order of the pontiff of the period, and each is preface by a special papal bull or letter.

See especially the Index of 1664, issued under order of Alexander VII, and that of 1761, under Benedict XIV.

Copernicus's statements were prohibited in the Index "donec corrigantur." Kepler said that it ought to be worded "donec explicetur." See Bertand, Fondateurs de l'Astronomie moderne, p.57.De Morgan, pp.

57-60, gives the corrections required by the Index of 1620.