The world’s languages with clitic clusters pattern with four major types of the word order systems, depending on the presence or absence of the 2P condition and the parameter of clitic-verb adjacency. Bulgarian has a double-focus system of clitic placement (2P condition and clitic-verb adjacency), which has typological parallels outside Europe but lacks direct counterparts in modern European languages. Neither the analogy with standard 2P languages without clitic-verb adjacency nor the analogy with the Romance systems with vP-internal clitics captures the profile of the Bulgarian clitic syntax. Historically, the rise of the clitic-verb adjacency is an innovation of Bulgarian, but its exact time and triggers are unclear. The language of the Wallachian letters (ca. 1386-1509) has a marked tendency towards the clitic-verb adjacency and is typologically similar to Modern Bulgarian but still has residual #XP – CL – [Y] – V orders. This idiom spoken by the L2 speakers of Middle Bulgarian cannot be viewed as a source of the Modern Bulgarian but hints that the clitic-verb adjacency parameter could develop in the history of Bulgarian because of the contact influence on the part of some Non-Slavic clitic systems.