Free Besieged Planet Calculator

A planet is besieged when it sits between the two malefics, Mars and Saturn, with one on each side. The classical word for this in Greek is emperischesis, which translates roughly as “hemmed in” or “contained.” Antiochus of Athens, writing in the second century, treats it as one of a small set of geometric conditions a planet can land in. Bonatti picks up related ideas many centuries later in the Latin tradition and gives them the more dramatic siege metaphor that English translations inherited.

The picture is literal. Imagine the malefic on one side of your planet, blocking it from going forward, and the other malefic already behind it, blocking retreat. The planet's significations still have to come through, but they have to push through both pressures at once. That's the whole content of the doctrine. It isn't a verdict on whether the planet is “good” or “bad,” the way pop-astrology uses the word afflicted. It's a specific geometric pattern with a specific name.

Classical sources actually describe the configuration in three shapes, and most ranking pages quietly conflate them. There is besiegement by body (the corporal version: the two malefics and the planet are all in the same sign, with the planet between them in degree). There is besiegement by sign(the whole-sign version: the malefics are in the signs flanking the planet's sign on either side). And there is besiegement by ray (aspect rays from the two malefics striking the planet from opposite sides). Each one carries different weight in different traditions. The calculator above splits the first two cleanly so you can see which of them, if any, is firing in your chart.

A planet is besieged when it sits between two malefics (Mars and Saturn), and enclosed when it sits between two benefics (Jupiter and Venus). Traditional sources describe several related forms: bodily enclosure, enclosure by sign, and enclosure by rays. This calculator implements two conservative checks: sign adjacency and in-sign degree adjacency. It marks any contrary-to-sect malefic and notes when a close benefic ray mitigates the condition.

By sign (whole-sign enclosure)

The whole-sign rule is the cleanest sign-based version, and it is preserved in Al-Biruni's eleventh-century compendium. A planet in sign N is besieged if one malefic occupies sign N minus one and another occupies sign N plus one. So a Libra planet is enclosed when one malefic is in Virgo and another is in Scorpio. The actual degrees inside those signs don't matter for this check. The geometric fact is the adjacency.

In-sign check (within seven degrees)

The conservative in-sign check asks for the two flankers to sit inside the same sign as the planet, one at lower longitude and one at higher, both within seven degrees of the planet. Demetra George and other modern Hellenistic teachers reconstruct enclosure from primary sources that distinguish bodily enclosure from enclosure by rays. The exact treatment varies by source, so the seven-degree window here is a deliberately narrow implementation, not a claim that every traditional author used this same cutoff for bodily enclosure.

A planet can satisfy the by-sign rule and fail the by-degree rule, or vice versa. That's why the calculator surfaces both verdicts side by side instead of merging them into one yes-or-no light.

Bonatti's applying-and-separating refinement

For by-degree besiegements, the calculator also reads each flanker's motion against the target's motion, using the signed deg-per-day speed from the natal API. When the target is closing the gap to one malefic and widening from the other, the result picks up a “Bonatti dynamic” tag. That's the strict thirteenth-century horary version: a planet separating from one malefic and applying to another, described as a situation going from bad to worse. The static geometric verdict still fires regardless; the tag tells you whether the dynamic shape is also active.

One scope note: Mercury

The calculator does not classify Mercury as benefic or malefic. Hellenistic doctrine treats Mercury as variable: benefic when with benefics, malefic when with malefics. Modern Hellenistic authors (Brennan, George) split on whether to apply the variability rule mechanically, so this implementation omits Mercury from the flanker pool rather than picking a side. Practically, that means a Mars-Mercury-Saturn stack will not register as Mercury besieging anything, and a Jupiter-Mercury-Venus stack will not register as Mercury enclosing anything. Mercury itself can be besieged or enclosed; it just isn't counted as one of the flanking bodies.

The geometry runs in both directions. Swap Mars and Saturn for Jupiter and Venus and you get the condition Bonatti called aid, and that modern Hellenistic astrologers usually translate as enclosure by benefics. Same shape on the chart wheel, opposite tone. A planet flanked by Jupiter and Venus is being supported on both sides instead of pressed on both sides.

Medieval discussions often spend more time on the damaging case than on aid, so the diagnostic vocabulary for the negative case is usually richer. The positive case still has the same mechanical reality: the planet is held between the two benefics rather than the two malefics.

The calculator treats them symmetrically and adds a third state:mixed enclosure. That's when one side of the planet is held by a malefic and the other side by a benefic. Mercury at 5° Leo with Saturn at 1° Leo behind it and Venus at 9° Leo ahead of it is mixed. It is not besieged. It is not enclosed by benefics. It is being pulled in two directions at once, so the calculator reports it separately instead of forcing it into a positive or negative bucket.

One last asymmetry worth keeping in mind. Even when the geometry is favorable, an enclosure by benefics doesn't override other damage to the planet. A Mercury enclosed by Jupiter and Venus but also tightly opposed by Saturn from across the chart still has the Saturn problem. Enclosure isn't a shield. It is a bonus condition layered on top of everything else the planet is doing.

Sect is the day-or-night assignment that splits the seven traditional planets into a day team (Sun, Jupiter, Saturn) and a night team (Moon, Venus, Mars), with Mercury siding with whoever rose first. It is the most powerful filter in Hellenistic astrology and the one most modern blogs ignore.

Applied to besiegement, sect changes the severity score. The malefic of your own sect, called the in-sect malefic, behaves with discipline. The contrary-to-sect malefic, called the out-of-sect malefic, is the one ancient sources call truly damaging. So Mars in a day chart and Saturn in a night chart are the two planets that hit hardest. If your besieged planet is flanked by an out-of-sect malefic on at least one side, the calculator marks the severity elevated and tags which planet did the damage.

The same logic runs in reverse for benefic enclosure. Jupiter is the day-favored benefic and carries the strongest help in a day chart; Venus carries the strongest help at night. An enclosure anchored by your in-sect benefic is materially different from an enclosure anchored by the contrary one, even when the chart picture looks identical. Two charts with “the same” Mercury between Jupiter and Venus can read very differently once you know which one was born during the day.

If you want to see the full sect-aware testimony scoring stacked against everything else affecting a given planet, the bonification and maltreatment calculator uses these same sect rules and produces a numeric verdict per planet. This page handles the geometry; that one handles the judgment.

Classical and medieval astrologers had an out for besiegement, and many ranking pages don't mention it. If a benefic, Jupiter or Venus, casts an effective aspect ray into the besieged planet's degree zone, the besiegement is tempered or released. Later horary practice preserves the same general escape clause, though authors vary in how tightly they define the operative ray.

The intervening ray works because, in the older model, planets don't just sit in their bodies. They project influence through their classical aspects: conjunction, sextile, trine, square, opposition. A trine from Jupiter to a besieged Mercury puts Jupiter's presence onto Mercury's degree, even though Jupiter itself is across the chart. The Mars and Saturn siege still shows on the page, but Jupiter has crossed the threshold and stood next to Mercury. That changes the verdict.

The calculator looks for intervening rays inside three degrees, a tight implementation meant to avoid calling every loose benefic aspect a release. When it finds one, the result card adds a green badge naming the rescuing planet and the aspect. This is not the same as “Jupiter trines your Sun, you're fine.” It only fires when the besiegement actually exists in the first place.

One caveat. This calculator only applies the release rule to malefic besiegement. It does not claim that a malefic ray automatically cancels an enclosure by benefics; that question belongs to the wider condition judgment rather than this narrow geometry detector.

The Moon moves about thirteen degrees a day, faster than any other body in the chart. That speed matters a lot in horary, electional, and transit work, where the Moon quickly carries the chart's story from one planet to the next. In natal work, do not assume the Moon is automatically more likely to be besieged than every other planet just because it is fast. What matters is that a besieged Moon is usually interpreted with special weight.

The deep reason is what the Moon stands for. The Moon is the traditional significator of the body, of the immediate environment, and in horary tradition of the situation under question. So when the Moon is besieged, the older texts read it as a signal that the matter at hand is hemmed in: you can't move forward without hitting a problem, and you can't go back to where you were. Lilly treats a besieged Moon in horary as one of the standard reasons to consider the question itself blocked. The condition isn't about you the person; it's about the situation the chart is describing.

In a natal chart, a besieged Moon doesn't carry the horary meaning of “don't bother.” It does carry a meaning closer to: there's a real, structural pressure on the parts of life the Moon governs (body, mother, daily rhythms, emotional regulation), and the path through is going to require working with the pressure rather than around it. Whether that pressure is mostly pre-built (sign-based) or a lived-in day-to-day texture (degree-based) is one of the things the calculator splits open.

Besiegement and maltreatment overlap, and they aren't the same thing. Maltreatment is the broader Hellenistic verdict that a planet's significations are being damaged. Besiegement is one of seven specific conditions that can produce a maltreatment verdict. Treating them as synonyms collapses the distinction ancient astrologers worked hard to keep clean.

The two calculators on this site work that distinction differently. This page does pure geometry. Either the planet is enclosed by malefics or benefics in one of the defined modes, or it isn't. There's no scoring, no testimony stacking, and no overall verdict on whether the planet is in good shape. That's the right tool when you want to know “is this specific configuration present in my chart, and where.”

The bonification and maltreatment calculator stacks seven testimonies on each side and sums them per planet, with sect weighting baked in. Besiegement is one of those testimonies, and the bonification page will fold the verdict in automatically. The right tool when you want to know “on balance, how supported or how damaged is this planet.”

The two pages occasionally disagree, and it's informative when they do. A Mercury besieged by sign but rescued by an intervening Jupiter ray and supported by Mercury's domicile ruler will light up red on this page (the geometry is real) and still come back balanced or counteracted on the bonification page (the verdict accounts for everything else). That isn't a bug. It's the difference between detecting a pattern and judging an outcome.

Marie Antoinette was born November 2, 1755, in Vienna, with the Moon at 20°40' Libra. Mars sits at 16° Cancer and Saturn at 23° Capricorn. Her chart is often discussed as a besieged-Moon example, but the exact kind of besiegement matters.

Run her data through this calculator and the result is more specific than the usual “her Moon was besieged” shorthand. By sign, her Moon is in Libra, with the malefics in Cancer and Capricorn. Cancer and Capricorn are not adjacent to Libra, so the whole-sign besiegement rule doesn't fire. By degree, the malefics aren't inside Libra at all, so the in-sign besiegement rule doesn't fire either. On the calculator's strict geometry, Marie Antoinette's Moon is not besieged.

What is going on, then, is the third classical mode: besiegement by ray. Mars in Cancer squares Libra, and Saturn in Capricorn squares Libra from the other side. Both squares land within seven degrees of the Moon's position. The Moon takes a ray from Mars on one side and a ray from Saturn on the other, forming a T-square with the Moon at its apex. Demetra George includes this ray-based mode in her reconstruction, and older authors preserve ray-based containment language. It is outside this calculator's narrow sign and in-sign scope, but it is the reason the traditional Marie Antoinette claim is not the same as a simple sign-adjacent or bodily enclosure claim.

The reason this calculator focuses on sign adjacency and in-sign adjacency rather than the by-ray mode is scope. A T-square is a T-square in any framework; you don't need a specialized besiegement calculator to find one, and the aspect pattern scanner already handles it. Whole-sign and in-sign besiegement, by contrast, are the modes most other tools and articles quietly skip. This page keeps those checks explicit, narrow, and side-by-side, with sect and intervening rays accounted for.

For a chart with the Marie Antoinette pattern, the takeaway is that the familiar claim can be source-honest, but it's about ray geometry rather than sign or in-sign adjacency. Knowing which version is firing is the difference between citing tradition and understanding it.

Sources: Antiochus of Athens, Thesaurus (2nd century CE); Al-Biruni, The Book of Instruction in the Elements of the Art of Astrology (1029 CE); Guido Bonatti, Liber Astronomiae (13th century); William Lilly, Christian Astrology (1647); Demetra George, Ancient Astrology in Theory and Practice (Rubedo Press, 2019). Marie Antoinette chart data per AstroDatabank.