DE MONARCHIA OF DANTE ALIGHIERI
CHAPTER XIV: What one agent can do is better done by one than by many.
1. When it is possible to do a thing through one agent, it is better done through one than through more.  We prove it in this way: Let A be one agent able to accomplish a given end, and let A and B be two through whom the same thing can be accomplished. If the end accomplished through A and B can be accomplished through A alone, B is added uselessly, as nothing results from the addition of B which would not have resulted from A alone. Now inasmuch as every addition is idle and superfluous,  and every superfluity is displeasing to God and Nature, and everything displeasing to God and Nature is evil, as is self-evident; it follows not only that whatever can be done through one agent is better done through one than through more, but that whatever done through one is good, done through more becomes manifestly evil. Further, a thing is said to be better the nearer it approaches the best. Its end partakes of the character of the best. But what is done by one agent is nearer its end, and therefore better. That it is nearer its end we see thus: Let there be an end C to be reached by a single agent A, or by a dual agent A and B. Evidently the way from A through B to C is longer than from A straight to C. Now humanity can be ruled by one supreme Prince who is Monarch.
2. But it must be noted well that when we assert that the human race is capable of being ruled by one supreme Prince, it is not to be understood that the petty decisions of every municipality can issue from him directly, for municipal laws do fail at times and have need of regulation, as the Philosopher shows in his commendation of equity  in the fifth book to Nicomachus. Nations, kingdoms, and cities have individual conditions which must be governed by different laws. For law is the directive principle of life. The Scythians,  living beyond the seventh clime,  suffering great inequality of days and nights, and oppressed by a degree of cold almost intolerable, need laws other than the Garamantes,  dwelling under the equinoctial circle, who have their days always of equal length with their nights, and because of the unbearable heat of the air cannot endure the useless burden of clothing. But rather let it be understood that the human race will be governed by him in general matters pertaining to all peoples, and through him will be guided to peace by a government common to all. And this rule, or law, individual princes should receive from him, just as for any operative conclusion the practical intellect receives the major premise from the speculative intellect, adds thereto the minor premise peculiarly its own, and draws the conclusion for the particular operation. This government common to all not only may proceed from one; it must do so, that all confusion be removed from principles of universal import. Moses himself wrote in the law that he had done this; for when he had taken the chiefs of the children of Israel, he relinquished to them minor decisions, always reserving for himself those more important and of larger application; and in their tribes the chiefs made use of those of larger application according as they might be applied to each tribe. 
3. Therefore it is better that the human race should be ruled by one than by more, and that the one should be the Monarch who is a unique Prince. And if it is better, it is more acceptable to God, since God always wills what is better. And inasmuch as between two things, that which is better will be likewise best, between this rule by "one" and this rule by "more," rule by "one" is acceptable to God not only in a comparative but in a superlative degree. Wherefore the human race is ordered for the best when ruled by one sovereign. And so Monarchy must exist for the welfare of the world.
1. Moore shows that the basic idea of this chapter is found in many places in Aristotle: De Part. Anim. 3. 4; Phys. 7. 6, etc. This idea reappears in Quaestio de Aqua et Terra 13. 34 (Oxford ed.): "Quia quod potest fieri per unum, melius est quod fiat per unum quam per plura."
2. Another common Aristotelian notion. See De Caelo 1. 4; De Gen. Anim. 2. 6.
3. "Equity." Dante writes -- one of the Greek words that found their way into mediaeval translations of Aristotle, and were "cruelly mauled by the scribes," says Wicksteed. The reference is to Eth. 5. 10: "And this is the nature of the equitable, that it is the correction of law, wherever it is defective owing to its universality."
4. The Scythians were vaguely understood to be the nomad tribes north of the Black Sea and the Caspian. Dante speaks of them again, De Mon. 2. 9. 3; 3. 3. 1.
5. Ptolemy's , or climates were belts of the earth's surface, divided by lines parallel to the equator. The length of day determined the position of each terrestrial climate, each having half an hour more than the preceding one. The seven climates of the northern hemisphere are described by Alfraganus in his Elementa Astronomica. The system of climates developed into that of the present parallels of latitude. Our word "climate" came from the application of a place name to the temperature of the region. See Toynbee's Dict. s. v. "Garamantes." Cf: Conv. 3. 5. 8.
6. The tribes south of the Great Desert were known as the Garamantes. See Lucan, Phar. 4. 334; 9. 369. In Conv. 3. 5. 8 they are described as men "who go almost always naked."
7. Exod. 18. 17-26; Deut. 1. 10-18. Moses as lawgiver is frequently quoted in this treatise on Monarchy: 2. 4. 1; 2. 13. 2; 3. 5. 1, etc. Moses is honored together with Samuel and John in Par. 4. 29 as those who "have most part in God."