The traditional view is that the Balto-Slavic languages split into two branches, Baltic and Slavic, with each branch developing as a single common language (Proto-Baltic and Proto-Slavic) for some time afterwards. Proto-Baltic is then thought to have split into East Baltic and West Baltic branches. However, more recent scholarship has suggested that there was no unified Proto-Baltic stage, but that Proto-Balto-Slavic split directly into three groups: Slavic, East Baltic and West Baltic. Under this view, the Baltic family is paraphyletic, and consists of all Balto-Slavic languages that are not Slavic. This would imply that Proto-Baltic, the last common ancestor of all Baltic languages, would be identical to Proto-Balto-Slavic itself, rather than distinct from it. In the 1960s Vladimir Toporov and Vyacheslav Ivanov made the following conclusions about the relationship between the Baltic and Slavic languages: a) Proto-Slavic language formed from the peripheral-type Baltic dialects; b) Slavic linguistic type formed later from the Baltic languages structural model; c) the Slavic structural model is a result of the Baltic languages structural model transformation. These scholars' theses do not contradict the Baltic and Slavic languages closeness and from a historical perspective specify the Baltic-Slavic languages evolution.