Anima Astrologiae or A Guide for Astrologers by William Lilly 1676

The 60th is to Consider, Whether the significator be in a Sign fixed, common, or moveable; because in a fixed Sign he signifies stability and countenance of the thing begun, or to be undertaken, or enquired of, In a common Sign, a change with a return or repeating of it, that the same will once be broken off, and afterwards begun again, or something added, or other alteration happen; for which reason in things that require alteration, as buying, selling, or the like, we should put the Significator and Moon, or one of them, into a common sign, but in a moveable Sign it signifies a sudden change, a quick despatch or end whether good or evil. And therefore in matters where we desire a sudden conclusion, we ought to put the Significator in moveable Signs; but things that we desire should be fixed and endure, we ought to place them in fixed Signs, there we would have a mean, let them be in common Signs, understand the same always of the nature of the Moon, if at any tine that canst observe it.

61.Whether the Lord of the Ascendant and Moon be with Dragons’ Head or Tail