The rule of the English law is directly the reverse, and the words of an engagement are to be construed most strongly against the person engaging. These two opposite rules have probably both resulted from the same maxim, that verbe ambigua fortius accipiuntur contra proferentem. By the Roman law, the words of the stipulation were necessarily those of the person to whom the promise was made; the person promising, only assented to the question proposed by the person stipulating. There is nothing similar to this in the covenants and engagements used in England; but an indenture is the deed of both parties and the words it contains are taken as the words of both, except as to those parts which are in their nature only applicable to one of them.
Robert Joseph Pothier
January 9, 1699 – March 2, 1772 A treatise on the law of obligations or contracts, vol.1, 1806.