With the introduction of coinage into European Greece, a change was made in the metal of the currency, for gold and electrum, which were plentiful in Asia, were not common in Greece proper, and a silver coinage was there the rule until Philip of Macedon took possession of the Thracian gold mines. The few gold issues before his time were due to exceptional circumstances; thus the gold coinage of Athens (No. =26=) was occasioned by great financial stress, when treasure was melted down to supply the currency. There was, however, no lack of gold money in Greece, for after the first electrum issues came the fine gold staters of Croesus, in the early sixth century (No. =27=; fig. 12_b_), and, on his overthrow by Cyrus, an international gold coinage was still available in the enormous issues of the Persian darics (No. =28=; fig. 12_c_), which were in common use all over the ancient world until the Macedonian gold replaced them. A few subsidiary electrum coinages survived in Asia, the most famous being the Kyzikene staters (No. =29=; fig. 12_m_), which were a standard exchange in the Aegean and Black Sea regions. A peculiarity of this coinage is that the distinctive type of the town, the tunny, is relegated to a secondary place, while the main type is a constantly changing design. In the piece illustrated the subject is taken from a group of the Athenian tyrannicides, Harmodios and Aristogeiton, which stood in the market place of their native city. [Illustration: FIG. 12.--GREEK COINS. 1:1.]