Anima Astrologiae or A Guide for Astrologers by William Lilly 1676

The 46th is, to see whether the Significator be a Fortune or Infortune, the first naturally signifies good and prosperity, the last naturally evil by its malignity; therefore consider the Planets’ places from the Ascendant where they are; for if a Planet be in his Light, or his Hayz in any of his Dignities, or in a good place from the Ascendant, it signifies good, and if it be a good planet the better.

47.Whether the Significator be in his proper Light