The term chariot is derived from the Greek lampēnē, a word which referred to a covered chariot used in the Greco-Roman period. The concept of chariot is primarily mentioned in ancient texts as a mitigating condition for planets that are under the beams. When a planet was in its chariot, it was viewed as being protected from the harsh rays of the sun. Thus, a planet under the beams could still be “strong” or “powerful” (dunatos), so long as it was in its chariot.
Antiochus and Rhetorius both considered a planet to be in its chariot when it was located in its own domicile, exaltation, or bounds. Porphyry stated that a planet was in its chariot if it was within its triplicity as well.
