Poems of Xu Hui
Autumn Winds in Box Valley, by Imperial Decree
Autumn winds rise in Box Valley.
Their strong spirits move rives and hills.
Pine trees lay flat on one thousand hillsides.
And rain falls between two crags.
Lowering clouds worry these marshes.
A setting sun spells disaster for the gate.
Now, above us, float these purple clouds.
With the return of true men, prophecy fulfilled.
In 648, Taizong entered into his last military campaign, north and west against the Uighurs. Apparently, the situation at Box Valley Gate, a strategic pass, was deteriorating. This poem seems to be either a rallying poem, prior to sending troops to remedy the situation or, more likely, a message to encourage complete victory as things have already gone well. "Purple clouds" are an auspicious sign in Chinese astrology. "Autumn winds" are a direct reference to a set phrase of "autumn winds scatter fallen leaves," which is the equivalent of "it carries all before it" in English. The Tang forces sweep away the enemy and must ensure the protection of Box Valley Gate -- or had best die in the attempt.
This poem is clearly a work poem for Xu Hui, marked as it is "by Imperial decree." While the timing of this poem does not validate her timeline, you can see that it harmonizes with it. This is the value of knowing what is "at least" true.