Scorched earth
A scorched-earth policy is a military strategy that aims to destroy anything that might be useful to the enemy while it is advancing through or withdrawing from a location. Any assets that could be used by the enemy may be targeted, for example food sources, water supplies, transportation, communications, industrial resources, and even the locale's people themselves.
Scorched earth
British monk Gildas, whose sixth-century treatise "On the Ruin of Britain" wrote about an earlier invasion "For the fire of vengeance … spread from sea to sea … and did not cease, until, destroying the neighbouring towns and lands, it reached the other side of the island."