In our great hall there stood a vacant chair,
Fashioned by Merlin ere he past away,
And carven with strange figures; and in and out
The figures, like a serpent, ran a scroll
Of letters in a tongue no man could read.
And Merlin called it “The Siege perilous,”
Perilous for good and ill; “for there,” he said,
“No man could sit but he should lose himself …”

Alfred, Lord Tennyson (1809-1892) English poet

Idylls of the King, “The Holy Grail” (1859-1885)

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