These philosophers, then, he dismissed with gifts; but to those who were in the highest repute and lived quietly by themselves he sent Onesicritus, asking them to pay him a visit. Now, Onesicritus was a philosopher of the school of Diogenes the Cynic. And he tells us that Calanus very harshly and insolently bade him strip off his tunic and listen naked to what he had to say, otherwise he would not converse with him, not even if he came from Zeus; but he says that Dandamis was gentler, and that after hearing fully about Socrates, Pythagoras, and Diogenes, he remarked that the men appeared to him to have been of good natural parts but to have passed their lives in too much awe of the laws. 4 Others, however, say that the only words uttered by Dandamis were these “Why did Alexander make such a long journey hither?” Calanus, nevertheless, was persuaded by Taxiles to pay a visit to Alexander. His real name was Sphines, but because he greeted those whom he met with “Cale,” the Indian word of salutation, the Greeks called him Calanus. It was Calanus, as we are told, who laid before Alexander the famous illustration of government. It was this. He threw down upon the ground a dry and shrivelled hide, and set his foot upon the outer edge of it; the hide was pressed down in one place, but rose up in others. He went all round the hide and showed that this was the result wherever he pressed the edge down, and then at last he stood in the middle of it, and lo! it was all held down firm and still. The similitude was designed to show that Alexander ought to put most constraint upon the middle of his empire and not wander far away from it.
Source: Plutarch Lives. Revised/translated by A. H. Clough. Revised from Dryden's version. Also known as “Parallel Lives”, written in Greek ~100 AD. Boston: Little, Brown and Company. 1859.