**Answer:**

**Pandit Ishwar Chandra Vidyasagar** was a renowned Indian social reformer, educator, writer, and philanthropist. He played a significant role in the Bengal Renaissance and contributed to various fields like education, widow remarriage, women's rights, and social reforms.

Ishwar Chandra Vidyasagar was appointed as the principal of the Sanskrit College in **1851**.

**Explanation:**

1. **Early Life and Education:**
- Pandit Ishwar Chandra Vidyasagar was born on 26th September 1820 in a poor Brahmin family in West Bengal, India.
- He showed exceptional intelligence from a young age and was proficient in Sanskrit, mathematics, and astronomy.
- Vidyasagar started his education in a village school and later moved to Kolkata for higher studies.
- He joined the Sanskrit College, Kolkata, to study traditional Indian scriptures and Vedas.
- Vidyasagar excelled in his studies and stood first in the Sanskrit College entrance examination.

2. **Appointment as Principal of Sanskrit College:**
- In **1851**, Ishwar Chandra Vidyasagar was appointed as the principal of the Sanskrit College in Kolkata, West Bengal.
- The Sanskrit College, established in 1824, was an institution for the study of traditional Hindu scriptures and Sanskrit literature.
- Vidyasagar's appointment as the principal was a significant milestone in his career and marked his dedication to educational reforms.

3. **Reforms and Contributions as Principal:**
- As the principal of the Sanskrit College, Vidyasagar introduced various reforms to modernize the educational system.
- He emphasized the study of English, mathematics, science, and social sciences alongside traditional Sanskrit literature.
- Vidyasagar introduced secular subjects and promoted a rational and scientific approach to education.
- He also revised the curriculum to make it more practical and relevant to the needs of society.
- Vidyasagar's reforms revolutionized the Sanskrit College and made it a center for modern education and learning.

4. **Legacy:**
- Pandit Ishwar Chandra Vidyasagar's tenure as the principal of the Sanskrit College had a lasting impact on education in Bengal.
- His reforms paved the way for the spread of modern education and the development of a rational and scientific mindset among students.
- Vidyasagar's contributions to education and social reforms earned him immense respect and recognition in India and abroad.
- He continues to be revered as one of the greatest social reformers and educators in Indian history.

In conclusion, Pandit Ishwar Chandra Vidyasagar became the principal of the Sanskrit College in Kolkata in **1851** and made significant contributions to the field of education through his reforms and modernization efforts.

He became principal in 1850, not 1851