General Book of the Tarot, by A. E. Thierens, [1930], at sacred-texts.com
There is much more mystery buried in every symbol than words spoken can tell. Superficial consideration might make astrologers wonder at this
image, which assimilates worldly power with the sign Cancer instead of with Leo, to which they are accustomed. Still there remains this to be taken into account, that originally 'emperors' got their power from the people,--China, Rome--long before they began to claim God as their private protector against eventual aggression from outside. The people are ruled by the sign of Cancer, says the astrologer. And thus originally the chosen emperor accepted vox populi as vox Dei. This chosen dignitary was nothing of a tyrant, originally, nor did he have anything to do with rulership or warfare: he was simply the highest and most pure expression of the soul of the people or nation. In China sometimes a poor but extremely virtuous old man without any other antecedents was elected to be emperor. All later usurpations of power and succession were deviations from the old and pure institution. The present position of the president in a republic comes very near to that of the original emperor.
The sign of the soul indeed is . . . Cancer. At the same time this is the sign of the breast (P.) and of the womb, as W. translates this passage about the card, which P. says is connected with the Hebrew letter Daleth. In the older pictures we see the effort to let the man make a figure 4 or something like the symbol for Jupiter with his crossed legs. There may be some meaning in it, but this seems futile with regard to the general significance of the Emperor as the representative of the past, of memory, tradition in the people and in family life, dharma and the real motives of the soul in the background of life, which actually rule life. It relates ..to every inner power of the soul from which outer activity (karma) will arise.
In different editions of the cards we find different sorts of sceptres in the hand of the Emperor. In some there appears also an eagle. We prefer the sceptre which Mr. W. puts into his hands: the crux ansata, symbol of the might of inner life, which rules matter. The planet Jupiter has only to do with this card, in so far as it is exalted in the sign Cancer, which means, that virtually hopes and expectations as well as ideals for the future take their origin in the deep-rooted attachments of the soul, which themselves are the expression of dharma or cosmic memory.
Still in a personal way the Emperor indicates the father of the querent, because it is from his father that his soul derives its elements. Compare in the horoscope the IVth house. Therefore this seemingly very feminine sign was symbolised by a male figure, while the seemingly male messenger was represented by a woman. The Empress indicates the spiritual parentage, the Emperor the physical one. The latter finds its counterpart (physical mother) in the Xth house, as is well known.
Some authors say this card means 'realisation.' That is correct so far as this word means an inner realising of the significance of outer facts: the gathering of the harvest of experience, which will become the store of memory.