Lady Mary Wortley Montagu and the Kit-Kats – illustration from Old and New London: A Narrative of its History, its People, and its Places (1873), by Walter Thornbury

(The Kit-Cat, or Kit-Kat, Club in London was a club of Whig politicians and men of letters founded in the reign (1685-8) of James II; its toasts were famous. Lady Mary Wortley Montagu (1689-1762) was an English aristocrat, letter-writer and poet.)

The practice of drinking a toast (that is, of drinking to the health, or in honour, of a person) originated, around 1700, in naming a lady to whom the members of a male club drank. The noun toast had long been used of a slice of toasted spiced bread with which beverages were flavoured, and the lady in question was regarded as figuratively adding piquancy to the beverage in which her health was drunk. This was explained in The Tatler of 21^st June 1709; a country gentleman asked the narrator “why do you call live people toasts?”:

I answered, “That was a new name found out by the wits, to make a lady have the same effect, as burridge* in the glass when a man is drinking.” (1831 reprint)

(* burridge: a variant spelling of borage; this plant was formerly largely used in making cool tankard (a cooling drink usually made of wine and water, and flavouring ingredients) and claret cup (a mixture of iced claret with lemonade and flavouring ingredients).)

The lady thus named often became the reigning belle of the season, as the same journal had explained on 2^nd June 1709:

(1831 reprint)
That happy virgin, who is received and drunk to at their meetings, has no more to do in this life but to judge and accept of the first good offer. The manner of her inauguration is much like that of the choice of a doge in Venice: it is performed by balloting; and when she is so chosen, she reigns indisputably for that ensuing year; but must be elected a-new to prolong her empire a moment beyond it. When she is regularly chosen, her name is written with a diamond on a drinking-glass. The hieroglyphic of the diamond is to show her, that her value is imaginary; and that of the glass to acquaint her, that her condition is frail, and depends on the hand which holds her. This wise design admonishes her, neither to over-rate or depreciate her charms; as well considering and applying, that it is perfectly according to the humour and taste of the company, whether the toast is eaten, or left as an offal.

This had first been mentioned by the English playwright, poet and member of the Kit-Cat Club William Congreve (1670-1729) in the comedy The Way of the World (1700); Mrs. Millamant says to Mrs. Marwood:

Marwood, you are more Censorious, than a decay’d Beauty, or a discarded Tost.

It is clear from the same comedy that drinking toasts was a privilege exclusive to men; Mirabell, a gentleman in love with Mrs. Millamant, tells her:

I submit.—But with proviso, that you exceed not in your province; but restrain your self to Native and Simple Tea-Table drinks, as Tea, Chocolate and Coffee. As likewise to Genuine and Authoriz’d Tea-Table talk,—such as mending of Fashions, spoiling Reputations, railing at absent Friends, and so forth—but that on no account you encroach upon the mens prerogative, and presume to drink healths, or toste fellows.

And, in The Careless Husband (1705), a comedy by the English actor, writer and theatre manager Colley Cibber (1671-1757), Sir Charles Easy says to Lady Betty Modish:

(1714 edition)
Ay, Madam, your Reputation—[…] ’t has been your Life’s whole Pride of late to be the common Toast of every publick Table, vain ev’n in the infamous Addresses of a marry’d Man.

This particular figurative meaning of the noun toast was naturally extended to a person (male or female) or thing that is very popular or held in high regard by a particular group of people.

Incidentally, the now familiar phrase toast of the town appeared in The Tatler of 8^th November 1709, albeit specifically applied to a reigning belle:

(1831 reprint)
I was very much surprised this evening with a visit from one of the top Toasts of the town, who came privately in a chair, and bolted into my room, while I was reading a chapter of Agrippa upon the occult sciences; but, as she entered with all the air and bloom that nature ever bestowed on woman, I threw down the conjurer, and met the charmer.

The noun toast soon took its other current figurative meaning: a call to a gathering of people to raise their glasses and drink together in honour of a person or thing. The following, by the English author and magistrate Henry Fielding (1707-54), is from The True Patriot: And the History of Our Own Times of 28^th January 1746:

(1767 edition)
When Sir John asked him for a toast, which you know is another word for drinking the health of one’s friend, or wife, or some person of public eminence, he named the health of a married woman, filled out a bumper of wine, swore he would drink her health in vinegar, and at last openly professed he would commit adultery with her if he could.