Still waters run deep

Still waters run deep is a proverb of Latin origin now commonly taken to mean that a placid exterior hides a passionate or subtle nature.

Formerly it also carried the warning that silent people are dangerous, as in Suffolk's comment on a fellow lord in William Shakespeare's play Henry VI part 2: According to The Concise Oxford Dictionary of Proverbs, the first mention of the proverb appeared in Classical times in the form altissima quaeque flumina minimo sono labi (the deepest rivers flow with least sound) in a history of Alexander the Great by Quintus Rufus Curtius and is there claimed as being of Bactrian origin.

In 1692 Roger L'Estrange included an outline of the Abstemius version in his edition of the fables under the title of A Country-man and a River, along with the interpretation that men of few words are dangerous: Slightly earlier than L'Estrange's translation, there was an amplified version of the story in La Fontaine's Fables under the title "The torrent and the river" (Le torrent et la rivière, VIII.23).

It tells of a man trying to escape a robber who easily fords a turbulent stream but drowns in a smooth-flowing river, ending on the caution that 'Silent folk are dangerous'.

In the background a capering donkey and a shrew are advancing along the road, watched by a woman whose hands are clasped by a sleek cat.