I’ve read three translations of the motto Sir Nicholas Bacon chose for his family crest, Mediocria Firma. Jardine & Stewart say, “moderate things endure” (p.28). Tittler says, “safety in moderation” (p. ?). He also notes that the phrase was probably taken from Seneca’s Oedipus. Wikipedia says “Moderation is stable.”
Google Translate produces “small firms,” which is a warning to those who imagine that might be a useful resource. Several sites on the web say, “Mediocrity is safest,” which is another bone-headed translation. The Bacons did not aspire to mediocrity.
Somewhere else I’ve read, “Moderate things are surest,” which is probably the best close translation, if not particularly witty. The meaning is clear: let moderation be your foundation, follow the golden mean, the middle way is safest and most reliable. Remember that Sir Nicholas kept his job as Attorney for the Court of Wards and Liveries through the reigns of Edward VI and Mary and survived to advance under Elizabeth I, the Queen of the Middle Way. He did it by presenting himself as a hard-working, apolitical, policy wonk.