To ensure that no one gained an advantage over anyone else, commercial law [in the 14th century] prohibited innovation in tools or techniques, underselling below a fixed price, working late by artificial light, employing extra apprentices or wife and underage children, and advertising of wares or praising them to the detriment of others.

A Distant Mirror: The Calamitous 14th Century (ed. Random House, 2011) - ISBN: 9780307793690