Talking of music reminds me of a remark of the learned Gentius, in one
of his notes on the _Gulistán_ of Saádí, that music was formerly in such
consideration in Persia that it was a maxim of their sages that when a
king was about to die, if he left for his successor a very young son,
his aptitude for reigning should be proved by some agreeable songs; and
if the child was pleasurably affected, then it was a sign of his
capacity and genius, but if the contrary, he should be declared
unfit.--It would appear that the old Persian musicians, like Timotheus,
knew the secret art of swaying the passions. The celebrated philosopher
Al-Farabí (who died about the middle of the tenth century), among his
accomplishments, excelled in music, in proof of which a curious anecdote
is told. Returning from the pilgrimage to Mecca, he introduced himself,
though a stranger, at the court of Sayfú 'd-Dawla, sultan of Syria, when
a party of musicians chanced to be performing, and he joined them. The
prince admired his skill, and, desiring to hear something of his own,
Al-Farabí unfolded a composition, and distributed the parts amongst the
band. The first movement threw the prince and his courtiers into violent
laughter, the next melted all into tears, and the last lulled even the
performers to sleep. At the retaking of Baghdád by the Turks in 1638,
when the springing of a mine, whereby eight hundred jannisaries
perished, was the signal for a general massacre, and thirty thousand
Persians were put to the sword, a Persian musician named Sháh-Kúlí, who
was brought before the sultan Murád, played and sang so sweetly, first a
song of triumph, and then a dirge, that the sultan, moved to pity by the
music, gave order to stop the slaughter.

To resume, after this anecdotical digression. Saádí gives this whimsical
piece of advice to a pugnacious fellow: "Be sure, either that thou art
stronger than thine enemy, or that thou hast a swifter pair of heels."