 Complete the following phrase:  In 427 BC, Cleon urged his Athenian countrymen to put to death the whole adult male population of Mytilene, which had put itself at the head of a revolt. His proposal, though at first accepted, was soon rescinded due to a protracted rebuttal by Diodotus. Nonetheless approximately one thousand chief leaders and prominent men of Mytilene were executed. In 425 BC, Cleon reached the summit of his fame by capturing and transporting to Athens the Spartans who had been blockaded at the 