Amicitia is the Latin term for friendship, and specifically, a political friendship. There could be a foedus amicitiae 'treaty of friendship' between Rome and another state or between Rome and an individual, generally called a client king.
Amicitia could also be the informal bonds of friendship.
Cicero may be at his curmudgeonly, Greek-philosophical best when he claims people must be good in order to be friends, but he makes points about friendship that transcend the Greco-Roman concepts, as indicated in this passage:
Now friendship may be thus defined: a complete accord on all subjects human and divine, joined with mutual goodwill and affection. And with the exception of wisdom, I am inclined to think nothing better than this has been given to man by the immortal gods. There are people who give the palm to riches or to good health, or to power and office, many even to sensual pleasures. This last is the ideal of brute beasts; and of the others we may say that they are frail and uncertain, and depend less on our own prudence than on the caprice of fortune. Then there are those who find the "chief good" in virtue. Well, that is a noble doctrine. But the very virtue they talk of is the parent and preserver of friendship, and without it friendship cannot possibly exist.
Cicero De Amicitia 1.6
- Howard Hayes Scullard , Andrew William Lintott "amicitia" The Oxford Classical Dictionary. © Oxford University Press 1949, 1970, 1996, 2005.
- "Encyclopedic Dictionary of Roman Law," by Adolf Berger; Transactions of the American Philosophical Society, New Series, Vol. 43, No. 2 (1953), pp. 333-809.