The Moons of Erdon


Erdon has fully 19 moons, which collectively are important to the sages for various portents and omens, and a number of other things, some of which involve the constellations of the stars. Their means of motion are somewhat peculiar as only one moon is ever prominent at a time. As these times are roughly equal in duration, each moon defines a month, which is usually 20 or 21 days. Most of the landmass of Erdon is in its northern hemisphere, including that of the large continent, so the following descriptions apply only to the northern hemisphere; the agricultural cycle of the southern hemisphere and equatorial regions are reversed or rather offset by 9 months (summer & winter are switched).

However, the barbarians and other peoples of the southern hemisphere mark their annual calendar primarily by the seasons and position of the sun. The southern months are traced out by the waxing and waning of Myrdle (The Constant Moon), as it seems to be the only moon on which time might be based in the southern hemisphere. In the southern hemisphere, “prominent” moons are actually the furthest away, and the rest are all so similar and constant in size that it would be more like keeping track of the “missing moon”, which their sorcerers and shamans have noticed. The alternate calendar can be found here.

As a matter of fact, there’s a classic joke that when the barbarians invaded Archlond, one of the Archon sages was pitted against a barbarian shaman; the sage won the duel simply by reciting the Archon method of chronology, which gave the shaman such a splitting headache that he dropped dead.

(#) Moon [proper] Common Name Appearance Month (days) [Associated] Season Effects [Associated]
0 Myrdle The Constant Moon All (30)0 All None
1 Myrdn The First Moon Nusef (19) Spring Arcane Magic, Magic Objects
2 Eyrdom The Imperial Moon Chunwe (21) Spring Geography, Survival
3 Myrdlis The Crystal Moon Zibagu (20) Spring, Rainseason Water, Storms, Floods
4 Myrtzul The Hallowed Moon Shauso (20) Summer Holiness, Protection
5 Myrdrelith The Blue Moon Narzoch (20) Summer, Earthquakes Earth, Dwarves
6 Myrtzn The Dark Moon Tearn (21) Summer, Wartime, Earthquakes* Darkness, Evil, Undead
7 Myrdech The Blood Moon Z’Khil (21) Summer, Wartime, Rainseason* Bloodlust, Rage, Lycans
8 Myrdchalt The Phantom Moon Tzyche (20) Fall, Wartime, Windstorms Incorporeals, Ethereals
9 Myrkwyn The Fire Moon Fumys (21) Fall, Wartime, Fireseason Fire, Heat
10 Myrdlycht The Broken Moon Rychte (20) Fall, Wartime, Stormseason Destruction, Chaos, Acid
11 Myrdolir The Half Moon Ixanu (20) Fall Balance, Neutrality
12 Myrdlon The Silver Moon Ketis (21) Winter Healing, Alchemy
13 Myrdkyl The Dragon Moon Kraln (21) Winter Dragons, Scalykinds
14 Myrdal The Jester’s Moon Bal (15) Winter, Festival Wine, Jubilation
15 Myrdraz The Ice Moon Zhant (21) Winter Cold, Ice
16 Myrdak The Storm Moon Gaulk (20) Winter, Stormseason Justice, Air, Lightning
17 Myrdunn The Jungle Moon Nerti (21) Spring, Rainseason Nature, Growth, Plants
18 Myrdranuch The Bright Moon Baast (21) Spring Light

0 Peoples who rely on the Constant Moon for their calendar use it to determine the span of their months, which average 30 days, in accordance with its cycle of waxing and waning. Also note, some peoples do not use the moons for their calendars in any significant respect, if at all.


This phenomenon may best be described to those familiar with but a single moon as that time when the moon appears so full, and so large that it seems to fill even the largest of streets (excluding some modern and futuristic boulevards). A moon, when prominent is generally the indisputably largest object in the evening heavens, and can even be larger than the sun (though its hard for most to make an accurate comparison for a number of reasons). The priests of Pelor (the sun god) say that the largest of Erdon’s moons will rival the sun in apparent size, and that’s good enough for most goodly folk. At any rate the “off-moons,” as they’re called, are all smaller and dimmer than in their prominence, and generally much smaller and dimmer than the Prominent Moon.

While in prominence, a moon appears to slow down so that it is visible each clear night and even some days, at least in the northern hemisphere. The remainder of the moons appear to move faster, and different off-moons are visible on different nights of the month. Despite the variance in apparent lunar speeds, the moons all always follow the same progression throughout the year. Moons on occasion cross paths, and it is usually the case that the prominent moon is one of these, and in such cases the prominent moon always remains visible (except Myrtzn, which technically isn’t visible, but it still blots out whatever goes ‘behind’ it). A moon’s prominence is sometimes colloquially referred to as its ‘prime;’ as in, “the Fire Moon is in its prime.” In fact, many who are aware of the the phenomenon hold “priming festivals” where they try to catch a moon as it “primes” (i.e. transitions to prominence) – a truly spectacular sight indeed; such events may be as simple as neighborly feasts, or as extravagant as a royal ball. Many a court astrologer is specifically tasked with discovering the hour of priming each month.

The phenomenon of lunar prominence is partly magical, and partly non-magical. Prominence is partly effected by Erdon’s atmosphere, which appears to disproportionately amplify luminosity and visual effects from the heavens; it also seems to be effected by the peculiar orbital system that the moons appear to follow; yet there also seems to be an overarching and mysterious force behind the whole phenomenon.


Despite the greater number and increased luminosity of some of Erdon’s moons, natural light during Erdon’s dark hours is not necessarily greater than worlds with fewer moons, especially when the moons are less than full (for those that wax and wane). This is partly due to Erdon’s atmosphere, which appears to reduce the luminosity of non-prominent moons, and which tends to be just as frequently overcast (and often more so) as any other world.

Prominent Moons
Most of the moons are light producers (reflectors actually), and tend to produce light in quantities up to that of a great full single moon when they are prominent. People under a clear open sky can generally see as far as the terrain will let them, and the light is less shadowy than that from a normal moon, and confers a +1 circumstance bonus on checks made to spot creatures hiding under the open moon. During the nights of a full (prominent) moon, moonlight tends to be even brighter, conferring a +2 bonus on spot checks to notice creatures hiding under the open sky. Furthermore, the range of light issued by an artificial source, such as a torch, or even magical light is half-again as far under a full prominent moon (e.g. a torch casts bright light up to 30 feet). Myrtzn is a notable exception that actually reverses this effect; as is Myrdolir, which keeps an even, standard luminosity throughout its prominence. Except during such months, humans in Erdon can generally see up to 10 feet clearly with no other light source; under a full (prominent) moon, the range of clear vision increases to 20 feet without aid. These benefits disappear whenever the sky is significantly obstructed, whether by cloud, canopy, or if under a crescent or new moon; under such circumstances men are rarely able to see even 5 feet ahead without some other light source.

Light From Other Moons
Because waxing and waning is usually determined by the relative positions of the celestial bodies (i.e. moons, sun, and planet), and because the moons are generally evenly dispersed about the surface of Erdon, never more than 5 of the moons (including the Prominent Moon) ever wax full simultaneously (i.e. the ones that can wax full). However, where this infrequent happenstance does occur, luminosity on Erdon’s surface is up to twice normal; i.e. men on such nights can generally see twice as far as they otherwise could, or about 40 feet clearly without aid. If but 4 moons are full (whether or not one of them is prominent), luminosity is merely half-again better than normal; i.e. a man could only see about 30 feet clearly if he had no other light. When only 3 moons are full (whether one of them is prominent or not), the benefit to a man is far less noticeable, conferring a mere quarter bonus to his visual range, or about an extra 5 feet (i.e. 25 feet) without other light. Fewer moons don’t appreciably enhance the brightness of light, unless a creature is gifted with low-light vision, in which case one of the moons must be prominent, and they can only see 5 feet further than normal (i.e. 45 feet). If only one moon is full, visibility should be normal if that moon is prominent. These benefits are only available under a clear sky (i.e. no clouds or trees above), and only if the participating moons are all wholly luminous moons (e.g. not Myrtzn or Myrdolir). Myrtzn effectively abolishes the bonus luminosity of such effects and then applies its darkness; i.e. 4 full moons (not including Myrtzn) only let a man see 5 feet in front of him during Tearn, if he has no other light.

Artificial Light and Moonlight
Artificial light sources improve such vision as they normally would, but when the ambient light is brighter than normal, brighter light sources than normal are required to actually improve the range of vision. For example, where a single torch might be sufficient to improve vision during a single (prominent) full moon, four torches, a campfire, brazier, or lantern are required to substantially improve visibility under 5 full moons. In the case of a moon such as Myrtzn, greater light sources are necessarily required to achieve even basic visibility, let alone superior visibility.

The Moons of Erdon

The Chronicles of Erdon Beaumains