Crenellated vs. Castellated — What's the Difference?

Crenellation refers to the architectural feature consisting of alternating high and low sections along the top of a wall, known as merlons and crenels (or embrasures), designed primarily for defense in fortified structures. Castellation, on the other hand, implies the architectural style that incorporates elements resembling a castle, including battlements, but often for stylistic rather than defensive reasons.

Crenellated walls were a practical design in medieval architecture, allowing defenders to take cover behind the merlons while firing arrows or throwing objects through the crenels. Castellated buildings might feature similar designs but are typically found in later periods where such defenses were no longer necessary, serving more as architectural homage to the medieval style.

The intention behind crenellation is rooted in military strategy and the need for protection, a requirement for building permissions historically granted through a royal or feudal license. Conversely, castellation reflects a romantic or nostalgic appeal to the feudal past, evident in country houses and estates built during the Gothic Revival period, where such features were decorative.

While both terms are often used interchangeably due to their visual similarities, the distinction lies in their original purpose and context. Crenellated structures had a clear defensive role in historical fortifications, whereas castellated structures adopted the appearance for aesthetic or symbolic reasons, often without the need for actual defense.

The presence of crenellation or castellation on a building today usually indicates either a preserved historical fortification or a more modern structure designed in the Gothic Revival or similar styles, paying homage to the architectural forms of the past.