Read this and answer the question. If the question is unanswerable, say "unanswerable".

Originally, legislative power was exercised by the sovereign acting on the advice of the Curia Regis, or Royal Council, in which important magnates and clerics participated and which evolved into parliament. The so-called Model Parliament included bishops, abbots, earls, barons, and two knights from each shire and two burgesses from each borough among its members. In 1265, the Earl of Leicester irregularly called a full parliament without royal authorisation. The body eventually came to be divided into two branches: bishops, abbots, earls, and barons formed the House of Lords, while the shire and borough representatives formed the House of Commons. The King would seek the advice and consent of both houses before making any law. During Henry VI's reign, it became regular practice for the two houses to originate legislation in the form of bills, which would not become law unless the sovereign's assent was obtained, as the sovereign was, and still remains, the enactor of laws. Hence, all acts include the clause "Be it enacted by the Queen's (King's) most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the authority of the same, as follows...". The Parliament Acts 1911 and 1949 provide a second potential preamble if the House of Lords were to be excluded from the process.

A bill could not become a law without whose assent?
the sovereign