Final answer:
In the fourteenth century, the Sultanate of Delhi extended its power into South India, facilitated the spread of Islam via taxation, and played a vital role in Indian Ocean trade.
Step-by-step explanation:
In the fourteenth century, the Sultanate of Delhi extended its power primarily into South India. By the end of Muhammad Bin Tughlaq's conquests in 1336, the Sultanate expanded almost all over the Indian subcontinent. This expansion was significant as it facilitated the spread of Islam and the imposition of a per-person tax on non-Muslims, which varied based on income. Despite this economic imposition, the sultans did not implement sharia law, likely to avoid major resentment among the local population. Moreover, the Sultanate of Delhi was a Muslim state that successfully defended itself against the Mongols and was an instrumental power in the Indian Ocean trade.