Three essential elements in the development of the European periphrastic perfect are explored, each of which demonstrates the important role played by areal diffusion. First, an east-west split in auxiliary usage is examined: HAVE developed as an auxiliary only in the west, while BE remains predominant in the east; convergence along linguistic borders is examined in some detail. Secondly, an explanation for this western predominance of HAVE is proposed: it is claimed that Latin formed its HAVE perfect on the model of Ancient Greek, with subsequent development of this construction in the Romance and other western European languages. Both the use of the HAVE auxiliary in Latin and the reinterpretation of the past passive participle as active are claimed to be due to Greek influence. Finally, the more recent shift of perfects from anterior or resultative to preterital meaning is presented as originating in Parisian French, and diffusing from there to other varieties within its realm of influence.