The CL protrahere and protractare seem to have both generated the OF purtreiter. Protrahere, also the etymon of purtraire, had the sense of 'to draw' or 'to make or represent by drawing' (DMBLS protrahere) while protractare equally had the sense 'to draw'. While the sense 'to shape, fashion' seem to derive from protrahere, the sense 'to portray, represent' could derive from either etymon.