After a time man learnt the use of metal. The smelting of iron was at first beyond his power, and he employed the mixture of copper and tin which we term bronze. Of this age specimens of winged celts and palstaves (a narrow hatchet, with a tang or socket for a haft) have been found in various parts of the county, as well as socketed celts, daggers, swords, spear-heads, and the like. The most important discovery of this nature was made in 1876 during drainage operations at Cumberlow Green, near Baldock, when some forty bronze implements were found in a well-like hole. Gold ornaments, probably referable to the same epoch, have been found at Little Amwell and at Mardox, near Ware. We now come to the early Iron Age, when man had succeeded in mastering this metal. Of this a very brief notice must suffice. Primitive coins, without inscription, of the type issued by Philip II of Macedon, and hence known as Philippi, were probably coined in the county in early British times; but after the Roman invasion a number of British coins were struck at Verulamium, among the most interesting of which are those of Tarciovanus, who reigned in that city from (probably) about 30 B.C. to about 5 A.D. A large number of his coins have been found at Verulam, as well as those of other British sovereigns. Tarciovanus, it may be added, was the father of Cunovelinus (Shakespeare’s Cymbeline), whose capital was Camulodunum, the modern Colchester. [Illustration: The Devil’s Dyke, Marford] Earthworks of great but unknown antiquity are by no means uncommon in Hertfordshire; one of the most important being Grimes-ditch, or Grimm’s Dyke, traces of which remain on Berkhampstead common, as well as on the opposite side of the Bulbourne valley, while a deep ditch runs in a bold sweep from near Great Berkhampstead through Northchurch and Wiggington to the north of Cholesbury camp, and thence into Buckinghamshire. Beech Bottom forms another great dyke lying between the site of Verulam and Sandridge, and is probably pre-Roman, and possibly connected with the encampment east of Wheathampstead known as the Moats or the Slad. The latter forms part of a great system of earthworks of which the opposite side is marked by the Devil’s Dyke at Marford. The great earthworks running outside of and parallel to parts of the Roman wall at Verulam are likewise older than the latter. Berkhampstead Castle may stand on the site of an earlier camp, as British and Roman coins have been found there; but the mound or keep, as at Bishop’s Stortford, Pirton, and Hertford Castles, is probably Saxon. On the other hand, the well-preserved camp near Redbourn, known as the Aubreys, Auberys, or Aubury, is certainly pre-Roman; and the same is probably the case with some of the numerous other earthworks dotted over the county, such as Arbury Banks, Ashwell. A few barrows or tombs of pre-Roman age have been opened and examined in various parts of the county, as at Therfield, Royston, and Easneye near Ware.