inroad

tunkeutuminen, hyökkäys an advance into enemy territory, an incursion, an attempted invasion
1776: Edward Gibbon, Decline and Fall of the Roman Empire, vol 1

The brave and active Contsantius delivered Gaul from a very furious inroad of the Alemanni;

And everywhere the people, or the populace, take their own government upon themselves; and open “kinglessness,” what we call anarchy, … is everywhere the order of the day. Such was the history, from Baltic to Mediterranean, in Italy, France, Prussia, Austria, from end to end of Europe, in those March days of 1848. Since the destruction of the old Roman Empire by inroad of the Northern Barbarians, I have known nothing similar.

... our whole great commercial system breaks down. It is breaking down, under the inroad of women who are adopting the unprecedented and impossible course of taking the system seriously and doing it well.

You must have been fairly surprised at Dr. Glaser's inroads into reprogramming the brain.

The Saracens (..) conquered Spain, inroaded Aquitaine. — Fuller.