Of armies on the chequer’d field array’d,
And guiltless war in pleasing form display’d;
When two bold kings contend with vain alarms,
In ivory this, and that in ebon arms.
Source, in full
"Caïssa: or, The Game at Chess" (wr. 1763), in Poems, Consisting Chiefly of Translations from the Asiatick Languages (1772) pp. 149–70. First two lines quoted in Willard Fiske, The Book of the First American Chess Congress (London: Sampson Low, Son & Co, 1859) p. 335. Compare: Marco Girolamo Vida, Scacchia Ludus (1527)