It has often been argued that the basic linear order of a lexical hea and its complement is determined on the basis of the directionality of θ-role assignment by the head at D-Structure. Essentially assuming this idea, Kemenade(1987)considers the following fact in early English: Vs and As assign θ-role to the left and Ns and Ps to the right in OE, but these four categories all θ-mark to the right in ME.
The present paper is an attempt to give an explanation to this fact within the GB framework. I make the following two claims. (i) Of all the lexical categories Ps first came to assign θ-role uniformly to the right in EME and their direction affected the directions of θ-role assignment by the other lexical categories. (ii) The first fixing of the direction of Ps'θ-marking is due to the fact that the functions of OE Case-endings were largely taken over by prepositions and word-order in EME.