(Disclaimer: the following is presented as a curious item of general information ONLY)
Regarding the Thema Mundi (and its legends), certain esotericists* in the latter part of the 1800's stated that the origin of planetary rulership is from the actual (ie astronomical) order of planets in a loop from the Sun out to Saturn and then "falling" on the end of the return loop, just before returning to the Sun, down to what they called "the final creation", ie, the Moon. Starting with Leo and the Sun (Leo the beginning of the creation circle because, as the Thema Mundi states, the earth was created when the Sun was in Leo), this loop (or as those esotericists called it, "the creation circle") goes like this:
Leo: Sun ---Virgo:Mercury (astronomically 1st from Sun)---Libra:Venus---Scorpio:Mars---Sagittarius:Jupiter---Capricorn:Saturn (end of loop, circle curves back heading back toward Sun), thus: Aquarius:Saturn (start of return loop at the "farthest extremity" from Sun)---Pisces:Jupiter (astronomically 1st planet "back" from Saturn)---Aries:Mars---Taurus:Venus---Gemini:Mercury---(then the "circle" or "loop" falls to the "last creation")---Cancer:Moon (and from the Moon, falls to the earth)
Another term for this circle or loop was "the path of the creative arrow", shot from the Sun, "bouncing" and turned by Saturn (double rulerships of Capricorn and Aquarius), returning toward the Sun, then "falling" to the Moon(Cancer) and landing with its creational input, upon the earth.
*I won't mention them because of the problems which arose on another Forum when I began elaborating about this subject.