Tectonic activity in the northern Apennines (Italy) is traced from the Oligocene to the Pliocene. The paroxysmal phase, extending from the middle Oligocene into the Aquitanian, was marked by positioning of the Tuscan and Ligurian nappes, shrinking of the crust, and folding of the autochthon. The present general topography of the northern Apennines can be attributed to activity during this phase. During the upper Tortonian second phase, movement was renewed and the two nappes assumed their present positions. The third phase, during the lower Pliocene, was marked by limited gravity sliding.