The chronology of the late Indo-Greek kingdom has been established by Bopearachchi and other scholars from numismatical evidence alone. The coins deteriorated continuously, the Strato coins being the most debased and crude in style, a striking contrast to earlier kings who struck some of the most beautiful coins of antiquity.
The decay was due to the increasing pressure of the Indo-Scythian nomads on the remaining Greek pockets, as well as their long isolation from the rest of the Hellenistic world.
Strato II, Strato III and Strato Dikaios struck debased silver drachms, which as mentioned portray Pallas on the reverse. Strato II appears as an old man with a sunken jaw on some of his coins, which is not surprising given that his grandson was co-regent.