a number of exclusive isoglosses in phonology, morphology, lexis, and syntax developed, which makes Slavic and Baltic the closest related of all the Indo-European branches. The secession of the Balto-Slavic dialect ancestral to Proto-Slavic is estimated on archaeological and glottochronological criteria to have occurred sometime in the period 1500–1000 BCE. A minority of Baltists maintain the view that the Slavic group of languages differs so radically from the neighboring Baltic group (Lithuanian, Latvian, and the now-extinct Old Prussian), that they could not have shared a parent language after the breakup of the Proto-Indo-European continuum about five millennia ago. Substantial advances in Balto-Slavic accentology that occurred in the last three decades, however, make this view very hard to maintain nowadays, especially when one considers that there was most likely no "Proto-Baltic" language and that West Baltic and East Baltic differ from each other as much as each of them does from Proto-Slavic. Evolution The imposition of Old Church Slavonic on Orthodox Slavs was often at the expense of the vernacular. Says WB Lockwood, a prominent Indo-European linguist, "It (O.C.S) remained in use to modern times but was more and more influenced by the living, evolving languages, so that one distinguishes Bulgarian, Serbian, and Russian varieties. The use of such media hampered the development of the local languages for literary purposes, and when they do appear the first attempts are usually in an artificially mixed style." (148) Lockwood also notes that these languages have "enriched" themselves by drawing on Church Slavonic for the vocabulary of abstract concepts. The situation in the Catholic countries, where Latin was more important, was different. The Polish Renaissance poet Jan Kochanowski and the Croatian Baroque writers of the 16th century all wrote in their respective vernaculars (though Polish itself had drawn amply on Latin in the same way Russian would eventually draw on Church Slavonic). Although Church Slavonic hampered vernacular literatures, it fostered Slavonic literary activity and abetted linguistic independence from external influences. Only the Croatian vernacular literary tradition nearly matches Church Slavonic in age. It began with the Vinodol Codex and continued through the Renaissance until the codifications of Croatian in 1830, though much of the literature between 1300 and 1500 was written in much the same mixture of the vernacular and Church Slavonic as prevailed in Russia and elsewhere. The most important early monument of Croatian literacy is the Baška tablet from the late 11th