Xiāngchuán zhè zuò miào yǐjīng yǒu yīqiān nián de lìshǐ le.
According to legend, this temple is already a thousand years old.
Tips
grammar
As a sentence opener, 相传 means 'legend has it that...' - introducing unverified traditional claims. As a verb after 代代, it means 'to pass down through generations.'