Poems of Xu Hui
Coming in to Taizong
As morning approaches this glistening tower,
Dressed and ready, I have a moment to myself.
Your daughter is full of smiles at your
Summons -- how could you come to me?
Even with only two poems and a little historical data, we can begin to know more about what must be true about Xu Hui. Let's construct a timeline in which her data points are restricted to the smallest amount of time with no time period less than a year. This gives us a picture of what must "at least" be true.
598 Li Shimin born to the Tang Emperor Gaozu
626 Li Shimin takes the throne as Taizong. He is 28.
627 Xu Hui born to the household of Xu Xiaode, an official in Changcheng, Huzhou. Taizong is 29.
647 Xu Hui enters the imperial household as a Talented Lady. It is likely that her father, who has educated her, petitioned for her admittance. She is one of nine with this status. She is 21 years old. Taizong is 49.
648 Xu Hui is promoted to one of the nine women of Handsome Fairness. Perhaps she has by now been noticed by Taizong. She is 22. He is 50.
649 Xu Hui is promoted to Complete Appearance, the only one of this status and one of nine ranked consorts. She is certainly in Taizong's confidance and company now. She may be in his bed but there is no point in guessing about this. Taizong dies in this year at the age of 51. Xu Hui is stricken by his death. She is 23.
650 Xu Hui dies of grief at the age of 24. Taizong's successor, Gaozong, posthumously promotes her to Virtuous Concubine and inters her in Taizong's tomb. Concubines were like wives, to some extent. So we are now more certain that Xu Hui and Taizong were lovers. But still, we could be wrong.
The above timeline is what must "at least" be true. Xu Hui could have come to the palace at fifteen. She could have been promoted for literary talent and later noticed by the emperor. But at some point, Taizong noticed her and valued her and promoted her to the high ranks of consorts.
In this poem, Xu Hui calls herself Taizong's daughter. So the two of them must be close. Close enough that she imagines him coming to her even though that is unlikely, possibly impossible. He must summon; she must go to him. Let's us say they were lovers. People might criticize them, anachronistically, for their age difference: 51 vs. 23. Recall that both Rubens and Kandinsky married sixteen year-olds in their fifties. Both, given all the historical evidence, were very happy marraiges. Maybe Taizong's final year or two were very happy ones for both himself and for Xu Hui. There is no reason this couldn't be the case.