The chief personal ornaments belonging to this later period, i.e. the ninth century onwards, are a number of remarkable objects known as Celtic brooches. The Celtic brooch, as far as its origin and development are concerned, shows no kinship with the bow or disc-shaped brooches already described, though, like them, it probably originated among the primitive Celts of the Danubian region. One theory derives its evolution from what is known as a ring-pin, that is a simple pin, the head of which, primarily solid, was afterwards pierced and fitted with a ring, which in course of time increased in size and became highly ornamented. Another theory traces the Celtic brooch from a combination of a long pin with the ancient dress fasteners--penannular rings furnished with knobs--such as are found in prehistoric graves, and are even now worn by the natives of West Africa. This penannular brooch has been found not only in Scotland and Ireland, but as far east as Livonia, and is actually still in use in Algeria at the present day. Its peculiarity consists in the great size of its pin--one in the British Museum measures 22½ inches--the length of the pin being supposed to have corresponded to the rank of its owner.[24] In some of the earlier forms the ring is of the same breadth all round, and merely cut across in one place for the passage of the pin. But as a rule this penannular ring terminates in knobs, and when the pin which travels round the ring has pierced the portions of the garments it is intended to unite, the ring is pushed a little to one side and prevented by the terminal knobs from becoming unloosened.[25] [24] _Proc. Soc. Antiq._, 2nd Series, XIX, p. 304. Such long stout pins could only have served to fasten coarse, loosely woven fabrics. [25] J. R. Allen (_Celtic Art_, p. 219) describes the exact function of this brooch, and illustrates its use in ancient and modern times. (See also _Reliquary_, 2nd Series, I, p. 162. 1894.) The developments in the form of this brooch show its evolution from a penannular to an annular ring. In some--probably the earliest--examples, the ring and the head of the pin terminate in bulbous knobs, or in spherical ends ornamented with Celtic designs and animals' heads. In others the ends of the rings and the pin-heads are broadened, in order to provide space for an elaborate surface decoration of interlaced work and zoomorphic and anthropomorphic designs similar to those upon the Irish manuscripts. Finally, the opening is closed and the ring becomes annular.