Abstract
This paper presents an analysis of the historical transitions of three types of English infinitival constructions: the accusative with infinitive (ACI) construction, the for NP to VP construction, and for to infinitives. It is argued that inflected infinitives in OE had an ambiguous categorial status between nominal and verbal and they lacked independent Tense node. This structure changed during ME along with the decline of the infinitival suffix -enne. First, in the mid-14th century, to was reanalyzed as Tense and consequently infinitives became more articulated than in OE. I claim that it was the immediate cause of the spread of the ACI to believe-type mental perception verbs and the rise of the for NP to VP construction. Then later in the mid-16th century, the ambiguity of categorial status disappeared, which led to the demise of for to infinitives. It will be claimed that these two changes were chronologically distinct processes.
