(acus) in ecclesiastical use. Pins made of precious metal, and, in later mediaeval times, enriched with jewels, were used for attaching the archiepiscopal (or papal) pallium to the planeta or casula (chasuble). The earliest mention of these is, probably, the description given by Joannes Diaconus of the pallium of Gregory the Great. Their first use, therefore, must probably date between the close of the 6th and the beginning of the 9th century. Innocent assigns to these pins a certain mystical significance.