History of the Peloponnesian War

After this, when their engines were of no avail, and the building of the wall was going on in opposition to the mound, the Peloponnesians, thinking it impossible to take the city by their present means of offence, prepared for circumvallating it.

First however they determined to make an attempt upon it by fire, [and see] whether with the help of a favourable wind they could burn the town, as it was not a large one: for they thought of every possible device, if by any means it might be reduced by them without the expense of a siege.