The historical nature of the phraseology is depicted at the base of historical dictionaries of Russian
and their card fi les. In our opinion, in the history of language some kind of pro-phraseological
fund, extensive group of combinations, actually a base for the idioms formation should be spoken
about. In diachrony steady combinations can be allocated at criteria of possible semantic shift and
even only a factor of frequent occurrence in the text. Th e criterion of expressivity and criterion
of stability cannot be considered obligatory for steady combinations in the history of language.
Variability is a very important feature of functioning of steady combinations in diachrony. First,
the component structure of phraseological unitsis varied though the conclusion about obligation
/ optionality of components can be made in the history of language. only at the base of combination fi xation in the texts of this period. Secondly, wide variation of steady combinations takes
place at diff erent language levels (semantics and the same syntactic model are preserved when
phraseological unit components (or their forms) are varied): we can distinguish word-formation
variation of separate components, derivation and grammatical variation, grammatical variation,
lexical variation.