Infinitive clauses and dative subjects in Russian

In this paper, I will account for the differences between Old Russian subordinate non-finite constructions functioning as complements and their Present-Day Russian counterparts, and explain the diachronic change between them. Nowadays, these Russian structures can only be instances of Obligatory Control, headed by NP-traces in [-tense] structures, while their Old Russian counterparts displayed No Control, and were headed by null pro subjects or overt dative subjects in [+ tense] structures. The change from No Control to Obligatory Control and the consequent loss of overt dative subjects in these constructions, as well as the rising of Non-Obligatory Control in the rest of non-finite constructions, was triggered by the loss of pro-drop in Old Russian, which produced a chain reaction: 1) pro was lost as a lexical item of the Russian lexicon, and became a 'last resort' pronominalization; 2) learners 'posited' a NP-trace instead of pro in subordinate non-finite clauses, whenever possible; 3) No Control changed into Obligatory Control in subordinate non-finite constructions in complement function; 4) the feature [+/- tense] of non-finite T shifted, banning the possibility of having overt dative subjects in these structures; 5) subordinate tensed clauses with an overt C were established as the only ones that displayed obviation effects.