This paper retraces two waves of palatalization in the forming of Western Romance varieties. The postulated processes are framed within the context of the general evolution of the phonological system, in the belief, too often disregarded, that the only good reconstruction is a structural one. The results may bear fruit for typological reflection. The paper also provides new evidence of an ancient division between a northern (Lugdunensis) and a southern part (Narbonensis) of Western Romania, as proposed by Lausberg.