Invasion represents warfare's most overtly aggressive form, the deliberate crossing of borders to seize territory or power by force. Poets have used invasion imagery to explore themes of violation, displacement, and the trauma inflicted upon populations whose homelands become battlegrounds through no choice of their own, the term carrying particular weight in poetry emerging from nations that have experienced foreign occupation and the lasting scars such incursions leave behind.

An invasion is a large-scale military incursion into foreign territory, typically aimed at conquest or occupation. Invasions are the ultimate act of aggression in international relations, requiring massive logistics and firepower. They can be amphibious, airborne, or land-based, each with its own challenges. In poetry, the invasion is the intrusion of the foreign, the loss of home and homeland. Related terms include incursion, assault, and occupation. The experience of invasion, from the perspective of both invader and invaded, has produced a vast literature. The invasion's aftermath, with its destruction and changing of borders, shapes the political landscape for generations.