Piers Kelly writes:

On the 15 February, 1839, a full 172 years ago tomorrow, The Sydney Monitor and Commercial Advertiser published the following:

That the posties are described as ‘messengers of love’ with ‘flushed countenances and sweating brows’ suggests that their present reputation for hanky-panky has an impressive pedigree. But what of the ‘hearts and darts and true lover’s knots’?

Unsurprisingly, ‘hearts and darts’ were illustrations on the theme of Cupid and a satirical essay in an English men’s mag of 1738 gives a neat example:

Plato […] has ordained amongst his laws, that whoever had performed any signal Exploit in War, should have the Right of demanding a Kiss, or even a greater Favour, from any of his Country-women. […] Of these Veterans I would have a Society formed, and incorporated by Letters-Patent, by the Style and Title of The Band of Old Lovers. They should be distinguished from other persons of the fame Quality by their Tunics or Robes of Ceremony made of Flame-coloured satin, and embroidered with flying Cupids, Hearts and Darts

From a search of Google Books it seems that an additional meaning of ‘idle romantic talk’ emerged later in the 19th century. Meanwhile, a true lover’s knot involved the attachment of two separate pieces of cord as a symbol of love.

A few years earlier, on 18 February 1837, The Sydney Gazette and New South Wales Advertiser printed an extraordinary story:

If I were that convict tailor I’d be feeling the dart rather more than the heart.

So this Valentine’s Day, make like it’s 1837. Say it with a poem read out during your trial by the presiding magistrate.