The Greenland Caledonides have a tectonic architecture built of Laurentian-margin Precambrian crystalline complexes and younger sedimentary successions that were metamorphosed during the Paleozoic collision with Baltica. Caledonian metamorphic patterns correspond to the gross structural levels of the orogen. The patterns are superimposed on earlier metamorphic histories in the Precambrian crystalline complexes, but they account for the sole metamorphism of Neoproterozoic to early Paleozoic sedimentary units. We describe the Caledonian metamorphism by dividing the orogen into two parts, a northern and a southern segment separated at 76°N by Bessel Fjord. North of Bessel Fjord, metamorphic grade increases eastward toward the hinterland...