David Mellinkoff's The Language of the Law deep dives into the reasons for, and shows many examples of, the "doublet" construction in legal language ("to have and to hold," to "cease and desist," to "seise and convey." Originally the idea was to insure that the legal concept was captured by including both the Saxon and the Anglo-French words. Eventually the construction itself became a legal style even when the words on either side of the conjunction shared the same etymology. The article skips over the fact that Law French was the language of the law in England until the 16th century and into the 17th; the law reports (the equivalent of the Federal Reporter today) were written in a strange mixture of French with English words. Any comprehensive law library has the Selden Society's printing of these texts.