to the gates of the capital. On this occasion Taitsong resorted to
diplomacy and remonstrance. He rode almost unattended to the Tartar camp,
and reproached their chiefs with their breach of faith, reminding them
that on his sending one of his sisters to be the bride of their chief they
had sworn by a solemn oath to keep the peace. He asked: "Are these
proceedings worthy, I will not say of princes, but of men possessing the
least spark of honor? If they forget the benefits they have received from
me, at the least they ought to be mindful of their oaths. I had sworn a
peace with them; they are now violating it, and by that they place the
justice of the question on my side." The Chinese chroniclers declare that
the Tartars were so impressed by Taitsong's majestic air and remonstrances
that they agreed to retire, and fresh vows of friendship and peace were
sworn over the body of a white horse at a convention concluded on the
Pienkiao bridge across the Weichoui River. The only safe deduction from
this figurative narrative is that there was a Tartar incursion, and that
the Chinese army did not drive back the invaders. Their retreat was
probably purchased, but it was the first and last occasion on which
Taitsong stooped to such a measure.

The peace of Pienkiao was soon broken. The tribes again drew their forces
to a head for the purpose of invading China, but before their plans were
complete Taitsong anticipated them by marching into their territory at the
head of a large army. Taken by surprise, the Tartars offered but a feeble
resistance. Several of their khans surrendered, and at a general assembly
Taitsong proclaimed his intention to govern them as Khan of their khans,
or by the title of Tien Khan, which means Celestial Ruler. This was the
first occasion on which a Chinese ruler formally took over the task of
governing the nomad tribes and of treating their chiefs as his
lieutenants. Down to the present day the Chinese emperor continues to
govern the Mongol and other nomadic tribes under this very title, which