The letter of Celestine to the Bishops of Narbonne and Vienne, part of which we quoted on pp. 26-7, is probably about the earliest available reference to the use of the pastoral staff by members of the episcopal order. This brings the history of pastoral staves back to the early part of the fifth century, and shows that this special ornament was one of the earliest of the external symbols which the church has prescribed for its officers. [Illustration: FIG. 5.—POPE GREGORY THE GREAT WITH PASTORAL STAFF.] The staff was a rod of wood with a head either crutched or crooked, usually of one of the precious metals. The name suggests that the symbolism of the shepherd had entered largely into the ideas connected with it. It was carried by abbots and abbesses, by bishops, and, till about the tenth century, by the Pope; but with the rapid growth of the temporal sovereignty of the Papacy, the emblem purely associated with the special idea of spiritual pastorate was abandoned. In the old pre-scientific days it used to be stated that the Pope at no time carried a pastoral staff, though he did bear a _ferula_, or straight sceptre—the symbol of rule;[48] but this is at variance with the evidence of contemporary art. We must not leave the subject of the earliest form of ecclesiastical vestments without briefly noticing the ornamentation with which they were decorated. In the oldest representations of ecclesiastics which we possess, their vestments were represented pure white, ornamented with the _clavi_; these were generally black, though St Isidore refers to purple _clavi_. But other colours appear in very early frescoes and mosaics. These, however, are apparently arbitrary, the result of the notions of the painter on the subject of the artistic combination of colours. Nothing analogous to the 'liturgical colours' of late times is traceable in the early or transitional period of the history of vestments.