In Greek historic writings, [...] a legend surrounding the Pythagorean ideal of friendship. Pythias is accused and charged of creating a plot against the tyrannical Dionysius I of Syracuse. Pythias makes a request of Dionysius that he be allowed to settle his affairs on the condition that he leaves his friend, Damon, as a hostage, so if Pythias does not return, Damon would be executed. Eventually, Pythias returns to face execution to the amazement of Dionysius, who because of the sincere trust and love of their friendship, then lets both Damon and Pythias go free.
"Damon and Pythias" came to be an idiomatic expression for "true friendship". Thus, Denis Diderot's short story, "The Two Friends from Bourbonne" (1770), begins "There used to be two men here who might be called the Damon and Pythias of Bourbonne." The canines Bummer and Lazarus were eulogized as "the Damon and Pythias of San Francisco" upon Bummer's death in 1865
Cokes. Well said, resolute Numps! but hark you, friend, where’s the friendship all this while between my drum Damon, and my pipe Pythias?
Leath. You shall see by and by, sir.
Ben Jonson. Bartholomew Fair (1614)
---
And there rises up before me all that was there foreshadowed, and I see visions of Damon and Pythias, of life-saving crews and Red Cross nurses, of martyrs and leaders of forlorn hopes, of Father Damien, and of the Christ himself, and of all the men of earth, mighty of stature, whose strength may trace back to the elemental loins of Lop-Ear and Big-Tooth and other dim denizens of the Younger World.
Jack London. Before Adam (1907)
---
so I hope I shall find a heart in you willing to accomplish my request. Which if I may obtain, assure yourself, that Damon to his Pythias, Pylades to his Orestes, Titus to his Gisippus, Theseus to his Pirithous, Scipio to his Laelius, was never found more faithful, than Euphues will be to Philautus.