Athenæus
From the time of Homer onwards, Greek literature was full of songs celebrating friendship:—
“And in fact there was such emulation about composing poems of this sort, and so far was any one from thinking lightly of the amatory poets, that Æschylus, who was a very great poet, and Sophocles too introduced the subject of the loves of men on the stage in their tragedies: the one describing the love of Achilles for Patroclus, and the other, in his Niobe, the mutual love of her sons (on which account some have given an ill name to that tragedy); and all such passages as those are very agreeable to the spectators.” Athenæus, bk. xiii. ch. 75.
From Theognis
One of the earlier Greek poets was Theognis (B.C. 550) whose Gnomæ or Maxims were a series of verses mostly addressed to his young friend Kurnus, whom by this means he sought to guide and instruct out of the stores of his own riper experience. The verses are reserved and didactic for the most part, but now and then, as in the following passage, show deep underlying feeling:—
“Lo, I have given thee wings wherewith to fly
Over the boundless ocean and the earth;