Note 68
From Chapter 71 of the Decline & Fall

After the description of the Capitol, he adds,

statuæ erant quot sunt mundi provinciæ; et habebat quæ libet tintinnabulum ad collum. Et erant ita per magicam artem dispositæ , ut quando aliqua regio Romano Imperio rebellis erat, statim imago illius provinciæ vertebat se contra illam; unde tintinnabulum resonabat quod pendebat ad collum; tuncque vates Capitolii qui erant custodes senatui, etc.

He mentions an example of the Saxons and Suevi, who, after they had been subdued by Agrippa, again rebelled:

tintinnabulum sonuit; sacerdos qui erat in speculo in hebdomada senatoribus nuntiavit:

Agrippa marched back and reduced the &mdash Persians (Anonym. in Montfaucon, p. 297, 298).