History of the Peloponnesian War

In the end of this winter, the Boeotians took Oropus by treason. It had in it a garrison of Athenians. They that plotted it were certain Eretrians and some of Oropus itself, who were then contriving the revolt of Euboea. For the place being built to keep Eretria in subjection, it was impossible, as long as the Athenians held it, but that it would much annoy both Eretria and the rest of Euboea.