Across the Empire (纵横, pinyin: zongheng) is, by webnovel standards, an ancient relic. First published on JJWXC in 2005 (for reference, JJWXC itself was founded in 2003), it's one of the earliest court intrigue novels in the baihe genre. It was actually planned as a trilogy of novels chronicling the life and death of protagonist Lin Zong, but only the first volume was fully written. The author started the second volume, but discontinued it after eighteen chapters. In an addendum to the second volume, she provides an outline of how her planned story would have gone.
The protagonist Lin Zong is an interesting twist on the popular cross-dressing lead. She is, at the start of the novel, the only living child of Prince Chu, one of the emperor's brothers. We're told that, being a very sickly child, she was brought up as a boy in order to ensure her good health (this is a superstition/folk belief/tradition that's still extant in some communities; the idea seems to be that, if you raise a child as the 'opposite' gender, you confuse the malevolent forces responsible for their poor health).* So from a very young age, Lin Zong has been treated (and dresses as) a boy, and her father has even designated her his heir, but everyone knows that she was born a girl. This creates interesting tensions down the line.
*This was also the premise of the 2015 Taiwanese drama
Bromance, the most accidentally(?) queer cross-dressing drama I've ever watched. Seriously, the protagonist is easily readable as non-binary up to the very last frame of the drama.
Prince Chu is one of those extremely competent, charismatic, loyalty-inspiring princes who are the bane of their emperor brothers' existences. The emperor therefore devises a loyalty test: he arranges for Lin Zong to be married to a high-ranking young noblewoman named Chu Yanran, to see how Prince Chu will respond. Prince Chu and Lin Zong don't really have a choice but to accept the match (the other option is to kick off and basically start a rebellion), and so we end up with the rather surreal scenario of a lesbian marriage sanctioned, nay compelled, by an otherwise institutionally homophobic state.
( some mild spoilers ) I read the Chinese original of both volumes
here and
here on JJWXC.