It was a fancy of the eccentric Mr. Pratt…to propose a game of Chess to a friend after dinner without Chessboard and men, and stipulate that instead of describing the moves with the usual prosaic abbreviations, a sort of poetical paraphrasis in the shape of rhyming couplets should be adopted. A good deal of amusement was sometimes created by the difficulty the second player would have, not in answering his opponent’s move, but in finding an appropriate rhyme to describe his own. (source)

Peter Pratt was the author of The Theory of Chess (1799) and Studies of Chess (1808); the latter contains “Caïssa,” a poem by William Jones that describes the chessboard in a game played between two fairies:

Squares eight times eight in equal order lie;
These bright as snow, those dark with sable dye;
Like the broad target by the tortoise born,
Or like the hide by spotted panthers worn.
Then from a chest, with harmless heroes stor’d,
O’er the smooth plain two well-wrought hosts he pour’d;
The champions burn’d their rivals to assail,
Twice eight in black, twice eight in milkwhite mail;
In shape and station different, as in name,
Their motions various, nor their power the same.

Say, muse! (for Jove has nought from thee conceal’d)
Who form’d the legions on the level field ?

High in the midst the reverend kings appear,
And o’er the rest their pearly sceptres rear:
One solemn step, majestically slow,
They gravely move, and shun the dangerous foe;
If e’er they call, the watchful subjects spring,
And die with rapture if they save their king;
On him the glory of the day depends,
He once imprison’d, all the conflict ends.

The queens exulting near their consorts stand;
Each bears a deadly falchion in her hand;
Now here, now there, they bound with furious pride,
And thin the trembling ranks from side to side;
Swift as Camilla flying o’er the main,
Or lightly skimming o’er the dewy plain:
Fierce as they seem, some bold Plebeian spear
May pierce their shield, or stop their full career.

The valiant guards, their minds on havock bent,
Fill the next squares, and watch the royal tent;
Tho’ weak their spears, tho’ dwarfish be their height,
Compact they move, the bulwark of the fight.

To right and left the martial wings display
Their shining arms, and stand in close array.
Behold, four archers, eager to advance,
Send the light reed, and rush with sidelong glance;
Through angles ever they assault the foes,
True to the colour, which at first they chose.
Then four bold knights for courage fam’d and speed,
Each knight exalted on a prancing steed:
Their arching course no vulgar limit knows,
Transverse they leap, and aim insidious blows:

Nor friends, nor foes, their rapid force restrain,
By one quick bound two changing squares they gain;
From varying hues renew the fierce attack,
And rush from black to white, from white to black.
Four solemn elephants the sides defend;
Beneath the load of ponderous towers they bend:
In one unalter’d line they tempt the fight;
Now crush the left, anti now o’erwhelm the right.
Bright in the front the dauntless soldiers raise
Their polish’d spears; their steely helmets blaze:
Prepar’d they stand the daring foe to strike,
Direct their progress, but their wounds oblique.

Jones had written the poem in 1763 at the age of 17. In the poem the nymph Caïssa is pursued in love by Mars, the god of war. Initially spurned by Caïssa, Mars asks for help from Euphron, the god of sport, who then creates chess as a gift for Mars to win Caissa’s heart. Caïssa has since been known as the goddess of chess.

Jones would later coin the term Indo-European to name the common ancestor language of many Indian and European languages.

Facts, strengthened by analogy, may lead us to suppose the existence of a primeval language in Upper India, which may be called Hindi, and that the Sanscrit was introduced into it by conquerors from other kingdoms in some very remote age.The Sanscrit language, whatever be its antiquity, is of a wonderful structure; more perfect than the Greek, more copious than the Latin, and more exquisitely refined than either, yet bearing to both of them a stronger affinity, both in the roots of verbs and the forms of grammar, than could possibly have been produced by accident; so strong indeed, that no philologer could examine them all three, without believing them to have sprung from some common source, which, perhaps, no longer exists; there is a similar reason, though not quite so forcible, for supposing that both the Gothic and the Celtic, though blended with a very different idiom, had the same origin with the Sanscrit; and the old Persian might be added to the same family. (source)