The "perpetual calendar" is the legendary "solar calendar" in China, which is used to record the specific dates of the solar calendar and the lunar calendar in a period of time. It is worth noting that the "10,000 years" in the "perpetual calendar" does not mean that the time span recorded in the calendar is 10,000 years, but symbolically represents a long-span time period without demarcation.
There is a legend about the origin of "perpetual calendar" in history. In the Shang Dynasty, teenagers thought the four seasons were too chaotic, so they observed the changes of shadows in the sun. After many days of observation, the teenager gained something, so Wannian met the monarch with his own ideas.
The monarch is very happy to hear the idea of "ten thousand years". He is very happy that "ten thousand years" will come. The monarch built the sun and moon pavilion, the sundial platform and the leaky jar pavilion for "Wannian" and asked him to make a calendar. Although "Wan Nian" was assassinated because of the jealousy of the monarch, it was also a near miss. After decades of calculation and research, an accurate solar calendar was finally made.
"Wannian" has changed from a high-spirited teenager at the beginning to an old man with gray temples. He spent his whole life just to accomplish one thing, which touched his grandfather David, so the monarch named the calendar he made after "Wannian", which was later called "perpetual calendar".
The story of "Wannian" making a "perpetual calendar" has always been regarded as a legend in ancient China, and there is no relevant evidence to prove the authenticity of this legend. However, the unearthed Oracle Bone Inscriptions proves that the calendar of Shang Dynasty has reached a considerable level, which makes the legend consistent with reality, but it cannot be used as sufficient evidence to prove the truth of the legend. Therefore, whether the origin of the name "perpetual calendar" is due to "perpetual calendar" remains to be verified.