The Caledonian Orogeny was a significant mountain-building event that occurred during the late Paleozoic era, approximately 490 to 390 million years ago. It primarily affected regions that are now part of Scotland, Ireland, and parts of Norway and Greenland. This orogeny resulted from the collision of tectonic plates, leading to the formation of the Caledonian Mountains. During the Caledonian Orogeny, intense geological processes such as folding, faulting, and metamorphism transformed the landscape. The event is crucial for understanding the geological history of the British Isles and the development of the Iapetus Ocean, which existed before the collision of the landmasses.