Book review: Matheseos Libri VIII

Julius Firmicus Maternus (280-360 A.D.) was a Sicilian lawyer from the upper nobility who retired from his career in order to devote himself to science and literature. He wrote Matheseos Libri VIII around 330 A.D. and dedicated to his friend, the consul Lollianus Mavortius. The material used for this book is mainly from Greek astrology sources. 


The first chapter represents a letter written by the author to his friend Mavortius, Governor of the entire East. Mavortius was an intelligent and learned person who had lots of discussions with Julius Firmicus on many subjects, one being astrology. A big part of this letter is treating the conflict between astrologers and their opponents. To all the questions rose by those who deny astrology Julius Firmicus answers by showing that people can’t control anything in life, that Fate (represented by planets in his system) governs everything. He was a fatalistic astrologer who believed people can’t change their inherent destiny.


Here you can find a wide range of astrological subjects. The author writes about the signs, the exaltations and falls (he considers a planet is more fortunate in exaltation than in domicile), the Egyptian decans and terms, matutine and vespertine planets, duodecatemoria, houses, aspects, antiscia etc.

Matutine planets are those which rise before the Sun (oriental), vespertine are those which rise after the Sun (occidental). The duodecatemoria is a technique based on the degree a planet have in a sign to compute another position which will reveal the whole essence. But, there is a problem because the algorithm is erroneous. You can find the good one here.

The aspects between planets are analyzed like whole sign aspects, without orb, giving much importance to the direction from which are formed: a right aspect is made from the back of the sign (dexter), a left aspect is in front of the sign (sinister).


The first pages from Liber Tertius present Thema Mundi, the chart for the birthday of the Universe. This doctrine, writes Firmicus, comes by Mercury itself who transmitted to other intermediaries. Thema Mundi is a chart with all the planets in domicile at 15 degrees. I believe at least in this moment is much more mythology that science.

After that, you’ll find the explanations for the planets and luminaries in houses. I think the interpretations are quite delightful and a big part of them are matching with reality. The analyses always takes in account if the chart is diurnal or nocturnal, thus if the planets are in sect their effect is considerable better. Also, in many cases, the author introduces new aspects (very often the Moon), analyzes more than position in house, for example:

Mercury located exactly on the ascendant in signs in which he rejoices, in a daytime chart, makes philosophers, teachers of the art of letters, or geometers […]or men skilled in sacred writings. Often he makes orators and lawyers, especially if in this house he is in his own sign or in other voiced signs. If either the Sun, Saturn or Jupiter are in aspect with Mercury in this house, he will make great men crowned with wreaths for being famous in sacred matters. […]But if Mars is in opposition or in square aspect or together with Mercury on the ascendant, the native is attacked by a variety of continual evils.”

The main weakness of this text is that many interpretations are exaggerated and you’ll find death, dangers, prisons and generals, kings, fame very, very often. It is something characteristic for the old astrological texts. I think this can be overcome by trying to understand the essence of the prediction and not to take it literally. Let’s see an example:

“Mars in the seventh house, that is, on the descendant, indicates the greatest evils and enormous perils. He will make the natives suffer as criminals and murderers, be defendants accused as discoverers of new crimes; or they will be torturers, executioners or informers.”

Then another interesting part follows, where are analyzed the conjunctions of the planetary pairs made in every house by Mercury with the Sun, Saturn, Jupiter, Mars and Venus. The final part of the chapter presents the conjunction between the Moon and Pars of Fortunae placed in different houses and with different aspects. It is, in fact, a preamble for Liber Quartus.


This chapter is almost entirely dedicated to the analysis of the Moon symbolism in the natal chart. This reveals the importance of the Moon in traditional astrology and gives us plenty of information to use. Are presented the interpretations of the aspects made by the Moon with Saturn, Jupiter, Mars, Sun, Venus and Mercury. The analysis shows all the situations when the Moon is waxing or waning and the chart is diurnal or nocturnal.

Another part reveals the meanings of the conjunctions of the Moon with other planets on angles and the position “void of course”.

Also, great importance is given to the planet with which the Moon makes the last aspect and the first aspect, more clear, the planet from which is moving and towards which is moving. Especially, the first aspect that will make is very important. This technique is characteristic for horary nowadays, but the ancients used it extensively for natal charts. I think it is a very important issue in the natal chart and we should not overlook it. Let’s see an example:

“If the waxing or full Moon is moving away from Jupiter toward Venus, the parents will have great position and power; but the native will be estranged from them or early become an orphan; nevertheless, for him power, fame and high position are indicat
ed, but all over a period of time. Great good fortune also is gained through wives. These men are handsome, pleasing, and charming and obtain power through their grace and charm.” 

Other subjects from this chapter are the part of fortune, the part of daemon, the ruler of the chart, the climateric years, occupations, empty and full degrees and masculine and feminine degrees.

The method to determine the ruler of the chart it is certainly strange, from my opinion: the ruler is the planet which governs the sign where the Moon enters after she has left the natal sign (the next sign from her natal position). I don’t know what is the reason behind this algorithm, so I don’t give much credit on this technique. Still, the interpretations for every ruler – planet are valuable because we can use them even we found the ruler using another method.

About the occupation Firmicus considers that one of the planets Mars, Venus or Mercury indicates what will happen. One must select the planet which is on MC, in trine with MC or in angle. Hmm… Again an unusual technique for most astrologers.


Here the author presents the interpretations for the Ascendant and planets in every sign. Because in traditional astrology were used Whole Sign Houses, when the Ascendant is in a sign, automatically we know where is the Descendant, MC, IMC. Delineations for every aspect are made in the same manner like in the former chapters: detailed, clear, related with other planets position, exaggerated.


In the six book of Mathesis are presented the interpretations for the aspects between planets. After that you’ll find many examples of complex aspects characteristic for different types: ill people, incest, eunuchs, hermaphrodites, lyric poets, prostitutes, beggars, murderers, blindness, leprosy, mental affliction, wealth, frigidity etc. Probably are charts found in practice by the author, because for every situation he gives many details, almost describing an entire chart, for example:

“Dangerous blindness is also indicated by the Sun on the ascendant, Saturn on IMC and the Moon holding a right trine from the ascendant. If Saturn and the Moon are in tropical signs, or the Sun and Mars are in opposition with them, this combination always mean danger to the eyes”.

The final part is filled with interpretations for what the Greek called Chronocrator, the ruler of time.


Liber Septimus keeps presenting complex configurations like in Liber Sextus. Here the author presents aspects specific for: charts of exposed infants, charts of twins, charts of slaves, number of masters, parents as slaves, charts of animals, physical infirmities, death of parents, hostility to parents, orphans, number of marriages, lover of boys, number of wives, murder of spouses, kinds of mates, children, mental deficiencies, royal charts, violent death, court sentences, sexual desire, occupations. One can find a great number of examples but are not very well organised and I don’t think all are specific for their subject. Probably, like in the former chapters, are examples from his practical experience.


The last book of Mathesis starts with the analysis of the ninety degree from the Ascendant and Moon which should reveal the whole essence of the chart. It is another technique hard to explain.  After that are presented the signs which see and hear each other and the constellations with their interpretations when are placed on angles.

The book ends with an interesting section named Myrogenesis, a technique about forecasting from individual degrees. The author reveals the interpretations for every degree where the Ascendant can be placed. It is something similar with the Sabian Symbols. Of course, several problems rise like: the time of birth must be precise, the degrees from the tropical zodiac can be different from what he indicated. Anyway, even it is hard to believe, you may have surprises reading the forecast for your Ascendant degree. Let’s see two example:

“In the sixth degree [Libra] they will be wealthy and carry on great affairs” – Bill Clinton has the Ascendant at 5,30 degree in Libra

“Whoever has the ascendant in the eleventh degree of Virgo will gain fame and honor as an athlete will be rich and he husband of a wealthy woman; but he will die a violent death” – Roger Federer has the Ascendant at 11,01 Virgo


Conclusion.The book, which is one of the biggest texts that survives from that period, it is a testimony for what meant traditional astrology and for the great number of astrological techniques used by Julius Firmicus, Dorotheus of Sidon, Manilius that now are lost. Or, at least, are not used anymore, being considered obsolete. This book it is an invitation to discover a new world of astrology and, nevertheless, a different way of thinking.

The text is enjoyable, easy to read, clear and full of practical examples. It is not theory at all, everything is pushed toward concrete forecasting. Sometimes, exaggerating, the predictions give sentences hard to believe, fierce, cruel. It is, again, a characteristic of traditional texts of astrology and the readers should mitigate the weakness by understanding the reasons which stand behind every prediction
and not to take literally every proposition.

Overall, it is a good book and a pleasant lecture. My evaluation is 8,8.