This paper aims to account for the historical rise of for NP before infinitival clause when the matrix predicate is an adjective. First, the main arguments and the problems of the previous studies are discussed, most of which made a point of the reanalysis of benefactive dative NP governed by the matrix verb to the subject of the infinitival clause. Unlike Jespersen (1909-49, V), Lightfoot (1979), Fischer et al. (2000), etc., this paper argues that such a reanalysis did not play a role and English did not undergo structural reanalysis over time. It is also argued that Old and Middle English had the same double structure as Modern English, and that the only change is the replacement of dative inflection by the preposition for and the later spread of the for to the subject NP of the infinitival clause. Moreover, the previous debates as to the cause of the change in question, whereby such claims as the loss of case inflection (Nagai 1998, Fischer et al. 2000) and the change of word order (Fisher et al. 2000) are the most prominent, are not significant because there is little structural change. The loss of case inflection only caused the use of for instead of case inflection, and the word order change only caused the possible occurrence of the sentence-initial for NP to V.