There are three kinds of constitutions, and an equal number of perverted forms, which are, so to speak, corruptions of these. Constitutions proper are kingly government,  aristocracy, and timocracy. Timocracy is a form of government based upon an assessment of property, though most people are wont to speak of it as constitutional government simply. Of these, kingly government is the best and timocracy the worst.

The perversion of kingly government is tyranny: for tyranny is a vicious form of monarchy;the bad king, then, becomes a tyrant. Both are monarchies, but there is a vast difference between them; for the tyrant seeks his own interest, the king seeks the interest of his subjects. Tyranny is the opposite of kingly rule, because the tyrant seeks his own good; and of this government it is quite obvious that it is the worst of all. The association of father and sons has the form of kingly rule; for the father cares for his children and the association of master and slave is tyrannical; for it is the interest of the master that is secured by it. But this seems to be a legitimate kind of tyranny.

Aristocracy degenerates into oligarchy through the vice of the rulers, who, instead of distributing public property and honours according to merit, take all or most of the good things for themselves, and give the offices always to the same people, setting the greatest store by wealth; you have, then, a small number of bad men in power, in place of the best men. The association of man and wife seems to be aristocratic: for the husband bears rule proportionate to his worth, i.e. he rules in those matters which are his province; but he entrusts to his wife those matters that properly belong to her. But when the man lords it in all things, he perverts this relation into an oligarchical one; for he then takes rule where he is not entitled to it, and not only in those matters in which he is better. Sometimes, on the other hand, the wife rules because she is an heiress. In these cases authority is not proportionate to merit, but is given on the ground of wealth and influence, just as in oligarchies.

Lastly, timocracy degenerates into democracy: and indeed they border closely upon each other; for even timocracy is intended to be government by the multitude, and all those who have the property qualification are equal. Democracy is the least bad [of the corrupt forms], for it is but a slight departure from the corresponding form of constitution. The association of brothers resembles a timocracy; for they are equal except in so far as they differ in age. On this account, if they differ very widely in age, their friendship can no longer be a brotherly friendship. A democratic form of association is chiefly found in those households which have no master (for there all are on a footing of equality), or where the head of the house is weak, and every one does what he likes.

2) Aristotle’s idea on the the corresponding forms of Friendship:

In each of these forms of government friendship has place to the same extent as justice. In the first place, the king shows his friendship for his subjects by transcendent benefits; for he does good to his subjects, seeing that he is good, and tends them with a view to their welfare, as a shepherd tends his sheep.

The friendship of a father for his child is of a similar kind, though the benefits conferred are still greater. For the father is the author of the child’s existence, which seems the greatest of all benefits, and of his nurture and education; and we also ascribe these to our forefathers generally: and thus it is in accordance with nature that fathers should rule their children, forefathers their descendants, kings their subjects.

These friendships involve the superiority of one side to the other; and on this account parents receive honour as well [as service]. Moreover, what justice requires here is not the same on both sides, but that which is proportionate to their worth; for this is the rule of friendship also [as well as of justice].

The friendship, again, of man and wife is the same as that which has place in an aristocracy; for both benefit in proportion to their merit, the better getting more good, and each what is fitting; but this is the rule of justice also.

The friendship of brothers resembles that of comrades, for they are equal and of like age; but those with whom that is the case for the most part have the same feelings and character. And the friendship in a timocracy is of the same type as this; for the citizens here wish to be equal and fair; so they take office in turn, and share it equally: their friendship, then, will follow the same rule.

In the corrupt forms, as there is but little room for justice, so there is but little room for friendship, and least of all in the worst; in a tyranny there is little or no friendship. For where ruler and subject have nothing in common, there cannot be any friendship, any more than there can be any justice,—e.g. when the relation is that of a workman to his tools, or of the soul to the body, or of master to slave. The tools and the body and the slave are all benefited by those who use them; but our relations with inanimate objects do not admit of friendship or justice; nor our relations with a horse or an ox; nor our relations with a slave as such. For there is nothing in common between master and slave. The slave is a living tool; the tool is a lifeless slave. As a slave, then, his master’s relations with him do not admit of friendship, but as a man they may: for there seems to be room for some kind of justice in the relations of any man to any one that can participate in law and contract,—and if so, then for some kind of friendship, so far, that is to say, as he deserves the name man.

And so friendships and justice are found to some small extent even in tyrannies, but to a greater extent in democracies than in any other of the corrupt forms; for there the citizens, being equal, have many things in common.

The relationship between friendship and justice is quite intriguing. For, even though justice, in the broad sense, is the fullness and unity of all the virtues, friendship goes beyond justice. Where there is friendship, justice is not necessary. Yet where there is justice friendship is still necessary. This relationship could perhaps be explained by the previously mentioned point that a genuine friendship presupposes that the people involved are already just men. Yet friendship can provide things which mere justice cannot. While friendship is reciprocal, the principal virtue of a friend is to love rather than to be loved. While justice requires a strict reciprocity according to merit friendship can exist in an unequal relationship, because the inequality is in some way bridged by the love of the friends.