A brief is a written argument that is submitted to a court as part of a lawsuit, and it is a fair question to ask why something called a brief is usually anything but. Granted, brief is related to the Latin brevis, meaning short. Its immediate ancestor, however, is the noun breve, which refers to a letter issued by the Pope, less solemn than a papal bull, but authoritative nonetheless. This is where we get the legal sense of brief, which was originally synonymous with writ, an old-fashioned term for a document that initiates a lawsuit.
So a brief is not by definition a short document, but it doesn’t have to be long one either. In America, up to the early twentieth century, legal briefs typically consisted of just a few pages of legal citations and argument. In the 1908 case of Muller v. Oregon, a prominent Boston lawyer named Louis Brandeis caused a sensation by submitting a 113-page brief, bristling not only with case citations, but with medical and legal statistics to support his argument. After Brandeis won the Muller case; courtrooms across the country were flooded with briefs resembling Homeric epics – they became known as Brandeis briefs.