Anima Astrologiae or A Guide for Astrologers by William Lilly 1676

The 41st is, If an Infortune, being Significator, be in his own House or Exaltation, or in his own Terms or Triplicity, or in Angles or Succedent Houses; for by all these means he is fortified, and shall be counted strong as a Fortune.

42.Whether a Fortune be Significator