On February 29, 1856, local Chinese officials in Guangxi beheaded French missionary priest Auguste Chapdelaine — and handed his countrymen a pretext for war.
Chapdelaine (English Wikipedia page> | French) had gone illegally to the Chinese interior to proselytize Christianity.
The local mandarin Zhang Mingfeng was no doubt disposed to take such an harsh line against this provocation by virtue of the ongoing, Christian-inspired Taiping Rebellion, which had originated right there in Guangxi and was in the process of engulfing all of southern China in one of history’s bloodiest conflicts.
So Chapdelaine and his associates were snapped up, put to a few days’ dreadful torture, and on this date a Chinese convert and Chapdelaine were both summarily beheaded. (A female convert, Agnes Tsaou-Kong, expired under torture around the same time.)
Pietistic accounts of believers’ last extremes are here and here.
(Images from this French page.)
It took months for word of this martyrdom to reach French consular officials, and many months more for the gears of international diplomacy to turn — but when they did so, France pressed a demand for reparations.
Since pere Chapdelaine had been acting illegally in the first place, the Qing’s obdurate Viceroy Ye(h) adamantly refused to offer Paris satisfaction.
By 1858, this intransigence sufficed to license French entry (alongside Britain) into the Second Opium War, from which the Europeans won by force of arms a noxious treaty guaranteeing their right to push Christianity in China, extracting a couple million silver taels in damages, and (of course) assuring their right to traffic opium into China.
It would be rather ungenerous to hold all the ugly imperial consequences personally against our day’s martyr. August Chapdelaine was canonized by the Catholic Church in 2000 as one of 120 Martyrs of China.
China was not impressed by this celebration of a onetime colonial catspaw, and met the Vatican’s “anti-China” celestial promotion announcement with one of its own — charging that Chapdelaine “collaborated with corrupt local officials, raped women and was notorious in those areas [where he preached].”