Abstract: The mountain-road from Megara to Thebes has always been a highway of some importance. Rising from the Megarian plain, it wound upwards among the hills until it topped the pass leading to the harbour of Aegosthena, passing on the right the site of the modern Vilia; near this pass it joined another road running up from Pagae, the other Megarian harbour. From the nature of the ground the old road and the modern mule-track must have followed much the same lines. The rocky range of hills, over which the pass already mentioned leads, is Mount Carydi. The need of guarding such a strategic point, whence the Megarian plain and the land round Pagae could easily be overlooked, is clear at first sight; and in fact there are still standing two fine Greek towers on the southern side of the pass. These were first described by Buchon: they are also marked in the map accompanying a dissertation by Lebègue, and mentioned in his text.