How long did it take Chen Xuanzang to learn from Tianzhu in history?

According to the Biography of The biography of Master Sanzang written by Xuanzang's disciples, Master Xuanzang set out from Chang 'an in the third year of Zhenguan (AD 629) and returned in the nineteenth year of Zhenguan (AD 645), which lasted seventeen years. This number is testable and should be the most accurate.

Xuanzang's westward journey lasted 17 years, with a journey of 50,000 miles. He went to 138 countries and brought back 520 volumes of 657 Buddhist classics. After returning to Chang 'an, he worked hard to translate Buddhist scriptures and translated 1335 volumes in 20 years. He also translated China's Lao Zi and other books into Sanskrit and introduced them to India. He is regarded as one of the three great translators of Buddhist scriptures in ancient China.