ALSO POSSIBLE: I want to show youintroduce an old temple today. ALSO POSSIBLE: I want to introduce an old temple today.

我的猜测：In the year 686 AD, it was calledfounded as the "Lotus Temple"." 我的猜测：In the year 686 AD, it was founded as the "Lotus Temple."

NOTE: If there are many temples in China with that same name, add the word "the" before "Lotus Temple." 注：若中国境内存在多个同名寺庙，请在“Lotus Temple”前添加冠词“the”。(Many "蓮華寺" exists in Japan. Perhaps in China too?)

In the 26th year of the Tang Dynasty's Kaiyuan period (738 AD), Emperor Xuanzong of Tang ordered that a Kaiyuan Temple (must) be built in each province. In the 26th year of the Tang Dynasty's Kaiyuan period (738 AD), Emperor Xuanzong of Tang ordered that a Kaiyuan Temple (must) be built in each province.

“Must” isn’t wrong, but to me the sentence is more natural without it.

In the 26th year of the Tang Dynasty's Kaiyuan period (738 AD), Emperor Xuanzong of Tang ordered that a Kaiyuan Temple must be built in each province. In the 26th year of the Tang Dynasty's Kaiyuan period (738 AD), Emperor Xuanzong of Tang ordered that a Kaiyuan Temple built in each province.

Thus, it was renamed (as) Kaiyuan Temple. Thus, it was renamed (as) Kaiyuan Temple.

“As” isn’t wrong, but to me the sentence is more natural without it.

Thus, ithe Lotus Temple was renamed as a Kaiyuan Temple. Thus, the Lotus Temple was renamed as a Kaiyuan Temple.

If you visit many old cities in China, you might see many Kaiyuan Temples, which (or: that) have the same story. If you visit many old cities in China, you might see many Kaiyuan Temples which (or: that) have the same story.

If you want to say that all Kaiyuan Temples have the same story, you could say, “…many Kaiyuan Temples, all of which have the same story.”

If you visit many old cities in China, you might see many Kaiyuan Tsuch temples, which have the samea similar story. If you visit many old cities in China, you might see many such temples, which have a similar story.