The last king of the Wodeyar dynasty who was defeated by Hyder Ali was Krishnaraja Wodeyar II. Let's understand the background and events that led to this defeat:

Background:
The Wodeyar dynasty was one of the oldest and longest ruling dynasties in the southern Indian state of Karnataka. They ruled the Kingdom of Mysore for several centuries, beginning in the 14th century. The Wodeyars were patrons of art, culture, and literature, and their rule saw significant development in various fields.

Hyder Ali's Rise to Power:
Hyder Ali was a military commander who initially served in the Mysore Kingdom under the Wodeyars. He gradually rose through the ranks and became the de facto ruler of Mysore in the mid-18th century. Hyder Ali was an ambitious and skilled military strategist who expanded the boundaries of Mysore through a series of conquests.

Conflict with the Wodeyars:
The Wodeyar dynasty was weakened by internal conflicts and political instability during the 18th century. This provided an opportunity for Hyder Ali to strengthen his position and assert his control over the kingdom. He launched several military campaigns against the Wodeyars, aiming to establish his dominance.

Defeat of Krishnaraja Wodeyar II:
Krishnaraja Wodeyar II was the king of Mysore during the late 18th century. He faced numerous challenges during his reign, including the growing influence of Hyder Ali. In 1761, Hyder Ali defeated Krishnaraja Wodeyar II in the Battle of Ratanapura, also known as the Battle of Dodballapur.

Hyder Ali's victory in this battle marked a significant turning point in the power dynamics of the region. With this defeat, Krishnaraja Wodeyar II lost his authority and control over Mysore, and Hyder Ali emerged as the de facto ruler of the kingdom. This event paved the way for the rise of the Sultanate of Mysore under Hyder Ali and his son, Tipu Sultan.

In conclusion, the last king of the Wodeyar dynasty who was defeated by Hyder Ali was Krishnaraja Wodeyar II. The Battle of Ratanapura marked the end of Wodeyar rule in Mysore and the beginning of Hyder Ali's dominance in the region.