Geothermometric and geobarometric data from pelitic schists in the upper plate of the Forsa thrust in the northern Norwegian Caledonides are interpreted as recording part of the uplift trajectory of this area during erosion and slow cooling. A method developed in this paper for reconstructing the thermal history of orogenic belts from such data is based on a general mathematical description of thermal conduction in a lithospheric slab with an arbitrary initial temperature distribution and uplifted at a constant rate. With certain restrictions the uplift trajectory (Tz path) of any rock parcel can be calculated from only a few temperature-depth points along that uplift trajectory. By appling this method to geothermometry and geobarometry data from near the Forsa thrust we can (1) extrapolate Tz paths measured over a limited depth range upward to the surface, (2) recover geotherms present at various times during the uplift and erosion history of the mountain belt, (3) obtain Tz paths for rock parcels above and below those for which PT data are available, and (4) use PT data in combination with geochronological data to obtain accurate estimates of uplift rates. Our analysis suggests that shortly after nappe emplacement, the nappe stack was hot (near 800¿C in the lower part of the nappe stack), while the underlying autochthon was cold (near thermal equilibrium prior to nappe emplacement). The maximum burial depth of rocks near the Forsa thrust was probably between 35 and 60 km.