Yeşilırmak (river)

The Yeşilırmak, known as the Iris in antiquity, is a river in northern Turkey. From its source northeast of Sivas, it flows past Tokat and Amasya, crosses the Pontic Mountains and the Çarşamba Plain, reaching the Black Sea east of Samsun after.
Its tributaries include the Çekerek and the Kelkit.
It was mentioned by Menippus of Pergamon in the 1st century BC.
Strabo's Geographica describes it as flowing through Comana Pontica, the plain of Dazimonitis , and Gaziura before receiving the waters of the Scylax, then flowing through Amaseia before reaching the valley of Phanaroea.
Starting with Dionysius Periegetes, in his Periegesis of the World, the Iris is often confused with the Thermodon, which also crosses the Themiscyra Plain, with its mouth about 40 km further east; the Thermodon is much smaller and clearer.