section_path: History/Lunisolar calendars by dynasty/Tang dynasty Wùyín Yuán calendar
section_name: Tang dynasty Wùyín Yuán calendar
paragraph_text: Tang dynasty Wùyín Yuán calendar
  
  The use of syzygy to determine the lunisolar month was first described in the Tang dynasty Wùyín Yuán calendar (戊寅元曆; 戊寅元历; ' earth tiger epoch calendar ').