As I conclude my labors on a new translation of the Liber aggregationis, or Book of the Gathering, ascribed to Albertus Magnus—also known as The Book of Secrets of Albertus Magnus—I have been reviewing noted authors who studied it. One of these is Giordano Bruno, who was infamously executed by the Roman Inquisition for heresy in 1600. Among his extant writings on magic is the De magia mathematica, which contains the following seventeen canons derived from the former work.  (For ease of reading, Bruno’s references to page numbers have been dropped. The “science” of which he speaks is the science of magic.)

The General Doctrine of Albertus

Leaving aside those matters which have to do with the enigmas of practice, the chiefest and most approved things in this science—of which there are many—must be collected from the pre-eminent Albertus.

I. The first of these is that this science is good—on the authority of the Philosopher, who affirms every science to be of the genus of good things—and that if there be just complaints on account of it, these do not proceed from the science itself, etc.

II. Concerning the method of working, as he says, a good effect looks to a good planet, but an evil effect to an evil one—that is, to their hours and days.

III. On the seven chosen herbs possessing the influence of the seven planets, etc. The first of these, which is called Asphodel, is of Saturn.

IV. On the virtues of stones. The first of these is the Magnet, etc.

V. On the virtues of animals. Some of these he adduces as though by augmentation, etc.

VI. On the times and rulership of the planets and stars, of which above.

VII. On the effects pertaining to each of the planets. For he says that life is under Saturn, etc.

VIII. That those things which are seen in characters, enchantments, sorceries and speeches, as well as many very base things, which seem wholly impossible and without a sufficient cause, are not therefore to be despised.

IX. That in the souls of men there is a virtue of altering things, etc. From this it is plain that not all who know the theory and grasp the reason of this art can make the proper use of it, such as is wont to be found among the unlearned and foolish, who grasp little or none of the reason for its virtue and efficacy.

X. That the hours are to be observed, etc.

XI. That the art of making characters is one possessing efficacy from the mind which strives with a great desire, etc.

XII. That it must be known concerning things, that all incline towards themselves through their species and forms, etc.

XIII. That it has been said concerning the attraction and inclination of all like things to like, etc.

XIV. That every thing is full of marvelousness, etc.

XV. That the pure astrologer is not to be believed in referring all marvelousness to the heavens, etc.

XVI. That marvelousness can come forth from things in divers ways, and through the celestial virtues, etc.

XVII. That it must be noted concerning things that they are of what qualities, dispositions and properties, etc.

There follows a translated extract from De compositione imaginum septem planetarum, a work ascribed to the philosopher Balenus (or Belenus), who is probably better known as Apollonius of Tyana.

This tract is listed by Trithemius in his Antipalus maleficiorum, 1.3, par. 60; and it is found in St. Petersburg, BAN, Q. 537, ff. 66r–84r, as well as on the mutilated leaves of Ghent, Universiteitsbibliotheek, 1021A, ff. 20r–31v. A fuller translation will appear in my forthcoming Opus Imaginum, which I hope to see in print later this year.

Cautions to Be Observed in the Composition of Images

I. When thou wouldst work for some effect in the science of images, it is needful firstly to know this art by its rules, as it has been handed down by the ancients. Nor shouldst thou think it possible for thee to come to an effect by means of the work of images by chance; for many fools presuming so, have experienced not profit but loss. No art can be learned without a teacher, especially in matters of magic.

II. Secondly, after thou hast learned this art, and wouldst do aught by means of it, take care not to begin with any other than a suitable intention for what is to be done, neither hesitating nor doubting, but firm, steadfast and confident.

III. Thirdly, be clean of all pollution, so that thou art not disturbed in thyself by any crime. Let thy clothes be clean and well-smelling. And have all the things that are needful prepared about thee.

IV. Fourthly, take heed above all that thou shouldst not reveal thine intention or the work thou art going to do to anyone—neither before nor after thine operation—but proceed secretly in all things, and work silently, both with images and their burial.

V. Fifthly, let the place where thou workest be secret, far from all men, clean, clear and bright, when the operation is for good; but when it is for evil, let it be any sort of place: it matters not.

VI. Sixthly, believe thou that the spirits of the planets are able to effect what thou meanest to do—that their images serve not only their course, rising and setting, but hold sway also during their hours especially.

VII Seventhly, that thou shouldst believe it cannot be done otherwise than the art itself promises, trusting rather that it is wholly certain and necessary that what thou seekest shall come to pass; for the spirits of the planets swiftly obey a believing and confident soul.

VIII. Eighthly, that when the images are to be suffumigated, thou shalt suffumigate those which are for good operations with a good odor; and those which are for evil, likewise with evil odors.

IX. Ninthly, that if thou wouldst work for the good of some friend by means of the images of the planets, either for good or for evil, thou shouldst never be induced by any prayers or gifts to reveal to him the manner of thine operation.

X. Tenthly, if anyone asks some effect of thee, for good or evil, consent thou not thereto until he has bound himself by oath to remain ever silent; and say, to incite terror, that the effect will cease when the operation is revealed.