Bhagwan Shankaracharya was 8 years old when he left his house. He took sanyas at the age of 9 years. After that what he accomplished cannot even be conceived of today. Between the ages of 12 and 16 years, Bhagwan Shankaracharya wrote commentaries on Prasthanatrayi, 3 types of Prasthaan and 11 Upanishads. He wrote a commentary on Brahma Sutra. He wrote a commentary on Bhadarayana Maharishi Veda Vyasa’s Brahma Sutra. He wrote a commentary on Srimad Bhagavatam. It has been mentioned in “Shankar Digvijay” – “अष्ठवर्षे चतुर वेदान ते सर्व शास्त्र वित् षोडशे, कृत्वान भाष्यं द्वात्मनीशे मुनिरात्नादात I”
It further says “चतुर्वेदाष्ठ्मे, द्वादशे सर्व शास्त्र वित् I षोडशे सर्व दिग जयता I द्वात्मनीशे मुनिरात्नादात I — meaning at the age of 8 years Bhagwan Shankaracharya had studied the 4 Vedas. He had studied the Vedas, Puranas, Itihas by at the age of 8 years. He had become “द्वादशे सर्व शास्त्र वित् पूर्णरूपसे निष्णात पारंगत सिद्ध हस्त कौशल संपन्न प्रवीनम निपुनोदक्षो”. He had become a scholar by the time be turned 12 years. After that “षोडशे कृत्वान भाश्यम”, between the ages of 12 and 16, he had written commentaries on Prasthanatrayi, 11 Upanishads, Dharma Sutra, Srimad Bhagvatam and on the Geeta.
It has been further said, “षोडशे सर्व दिग जयता”, i.e., at the age of 13 years, he had set out for his campaign of world conquest. It was a start of a golden period in history. “द्वात्मनीशे मुनिरात्नादात”, i.e., at the age of 32 years, he attained moksha. He went Mount Kailash. At the age of 32 years…between the ages of 12 and 16 years he writes a commentary on Prasthanatrayi. After 16 years he travels across this holy land and creates a golden history. He set out to demolish people against the Vedas, traditions, rituals just as the sun destroys darkness.