During the Northern Song Dynasty, a prefect named Tian Deng ruled with tyrannical arrogance. Because his name was "Deng," he forbade anyone in his jurisdiction from uttering any word that sounded like "deng"—even homophones had to be replaced with other terms. Anyone who violated this taboo would be charged with "insulting the local magistrate," facing severe punishment: flogging for minor offenses, imprisonment for major ones. Many clerks and soldiers were beaten simply for accidentally saying a word that rhymed with "deng."
The annual Lantern Festival was approaching, and as was tradition, the prefectural capital would celebrate with three days of fireworks and lantern displays. The government office would post notices in advance, inviting the common people to come and enjoy the lights.
But this time, the official posting the notice found himself in a dilemma. Using the character "lantern" would offend the governor, but without it, the meaning wouldn't be clear. After thinking for a long time, the minor official could only change "lantern" to "fire." Thus, the notice read: "This prefecture, as per custom, will set fires for three days."
Once the notice was posted, the townspeople were thrown into an uproar. Travelers from afar, utterly baffled, truly believed the authorities were about to set the city ablaze for three days. Frantically packing their belongings, they scrambled to flee the scene of impending disaster.
The local people, already deeply resentful of Tian Deng's tyrannical and unreasonable rule, became even more outraged upon seeing this official notice, angrily saying, "Only the prefect can set fires, but the common people are not allowed to light lamps—what kind of world is this!"
Later, the idiom "Only the magistrate may set fires, but the common people may not light lamps" came to describe rulers who can act arbitrarily while the people's legitimate actions are restricted.
Source: *Lu You (Song Dynasty), "Old Hut Study Notes"*
Meaning of the Idiom: Later, the Chinese idiom "只许州官放火，不许百姓点灯" came to describe how rulers who can act arbitrarily while the people's legitimate actions are restricted.