Each sign of the Zodiac is divided into four essential Elements, these being of Fire, Air, Water and Earth. Since there are 12 signs and they are equalled divided by the 4 Elements to come to a sum of 3 which is the number of Triplicities or Signs in which fall into the 4 Elements. Three is also the number of Trine and therefore each of these Signs form a perfect trine, or perfect love between each other. This is agreeable because in order to be placed in a certain Triplicity, it must be of the same Element quality and therefore fire is with fire, air with air, & etc. The names of the Triplicities follow that of the Element in which they consist of, being the Fiery Triplicity, Airy Triplicity, & etc. The signs which are placed in the Fiery Triplicity are of Aries, Leo and Sagittarius; the Airy Triplicity are Gemini, Libra and Aquarius; the Watery Triplicity are Cancer, Scorpio and Pisces; and finally the Earthy Triplicity which consist of Taurus, Virgo and Capricorn. As aforementioned, each of these signs behold each other with a Trine aspect and therefore are in agreement with each other.
The first Triplicity is that of the Fiery Triplicity. It consists of the Planets Jupiter and the Sun. The Sun is the diurnal Triplicity and Jupiter is thus the Nocturnal. This means that when Jupiter or the Sun are found in either Aries, Leo, and Sagittarius, they are thus in their Triplicities. It is important to also note that it is more favorable if the Sun is in this Triplicity during a chart casted during the day and the reverse for Jupiter. The Sun is given the diurnal Triplicity of this Sign because he is by nature Diurnal and due to the extreme nature of the first part of the fiery Triplicity. Jupiter is given the night because his heat is abated and withheld with moisture and therefore is more Nocturnal. The ancient opinion is that there are three Planets in each Triplicity and the third of the Fiery Triplicity is considered that of Saturn, being the coldest part of the Triplicity and therefore abates the heat of the fire. This Triplicity is also considered the Oriental or Eastern Triplicity.
The second Triplicity is that of the Airy Triplicity. The Planets which are considered apart of this Triplicity are Saturn and Mercury. Saturn is the diurnal Planet of this Triplicity because Saturn has his House in Aquarius and his Exaltation in Libra, where as Mercury only has his House in Gemini and therefore Saturn is more powerful in an Airy Nature then that of Mercury and thus given the diurnal House. Mercury is contrarily given the Nocturnal House. The ancients also considered Jupiter to be apart of this House as well due to his temperate nature much as that of Air. This Triplicity, because it is of the Air is given the direction of the Occident or West.
The third Triplicity is that of the Watery Triplicity and consists of the Planet of Mars and thus given him chief dominion of the Watery Triplicity. Mars is both the Diurnal and Nocturnal Planet in this Triplicity. The purpose behind this because of Mars' unrestricted violent heat he is therefore abated by Water. For when he is placed in his House Sign he is given the power to produce mischievousness and violence, being of his nature and therefore he is temperate by the power of Water. The ancients consider the Moon and Venus to be apart of this Triplicity as well because Cancer is the House of the Moon and Pisces is the Exaltation of Venus and therefore they have joy in this placement. This Triplicity is given the dominion of the North.
The fourth Triplicity is that of the Earthy Triplicity and consists of the Planets Venus and the Moon because Venus finds her House in Taurus and Moon her Exaltation. The Triplicity is also feminine and Southern. Venus is the diurnal Planet because she has the most power being in her House where as the Moon is nocturnal Planet because she only has Exaltation in this placement and therefore is not as powerful as Venus.
The rank of Dignity for the Triplicity is ironically 3 (+3) and therefore any Planet placed in its Triplicity will receive this ranking.
