Triangles: Taurus Scorpio Pisces

Signs ruling the ‘three decanates’ of the entire zodiac

…just as each sign is divided into three decanates which are ruled by specific planets, so the zodiac itself is a part of a still greater zodiac and is also divided into three parts […] The three ruling constellations are Scorpio (on the fixed cross), Taurus (also on the fixed cross), and Pisces (on the Mutable Cross). …because testing, trial, desire, illumination, matter, form and salvation are the keynotes of our solar system and of our Earth in particular.

This solar system is … expressing the second aspect of divinity and hence the emphasis upon the forces pouring through Scorpio, Taurus and Pisces. […] A hint is there conveyed anent our zodiac which is of supreme importance to the astrologer of the future.

The passing from ‘test to victory’ in each sign of three great avatars:

Hercules—strength through testing–becoming the triumphant disciple.
Buddha—illumination through struggle–victory over desire and arrival at illumination.
Christ—resurrection through sacrifice–overcoming death to become the world saviour.

In a peculiar sense, these three constitute a triangle of initiation and are of paramount potency in the initiation process. They express strength, illumination and love in full expression.

These three constellations … form a triangle of initiation of profound importance because it provides those conditions and that energy which will test and perfect the three aspects of the personality so that they are true reflections of the three divine aspects; they concern soul and body primarily and therefore their expression is through the Mutable Cross and the Fixed Cross but not the Cardinal Cross.

NOTE: this is all directly from EA, needs an edit

1. Scorpio (appetite)
carries the test right down into the physical plane life, and then, when it is faced and handled there the life of the (person) is carried up into heaven, and the problem which the test involved is solved by the use of the reasoning mind. [Sacral-throat? Mars-Mercury?]
2. Taurus (desire)
governs desire and carries the test into the emotional or astral plane, and carries desire-sensitivity up from the form side of life into that world of sensitive perception which we call the intuitional plane. [Solar plexus-heart]
3. Pisces (self-will)
carries the test into the region of the mental processes, which is a reflection of the will aspect … the problem of the initiate in this sign is voiced by Christ in the words, “Father, not my will but Thine be done.” The tests carry the self-will of the personality up into the region of the divine will and the result is inspiration and the emergence of a world saviour.

Esoteric Astrology: 204-5, 486-7