It is evident there was no great and sudden change from the culture of the Stone Age to that of Bronze. It was as if the darkness of night had given place to the roseate light of dawn, to be shortly followed by the full day of historic times. It was probably introduced by trade. The articles introduced in this way would consist of simple implements, weapons, and ornaments. Following after the trade would be found the smelter with his tools, and, where the conditions were favorable, local manufactories would be set up. But this home industry would not prevent importation of more pretentious articles from abroad. This would account for the rich collections of shields, swords, and golden cups found in Denmark that betray an Etruscan origin. Investigations of recent scholars show that the bronze of the early Bronze Age came from Asia Minor. Subsequently there were three great centers of bronze production, each having certain styles. These were the Russian on the east, the Scandinavian on the north, and the Mediterranean on the south. If this view be correct, bronze must have been in use in the South of Europe long before it was in the North. This view of the introduction of bronze is, we think, that of the best scholars in Europe. Others, however, think bronze was brought in by the invasion of the Aryan tribes. Mr. Keary says: “The men of the Bronze Age were a new race, sallying out of the east to dispossess the older inhabitants, and if, in some places, the Bronze men and the Stone men seem to have gone on for a time side by side, the general characteristic of the change is that of a sudden break.”9 We have shown that it was carried to England by an invasion, and it was, perhaps, so introduced into Denmark, but in other countries of Europe by trade.10