The foreign power that was defeated by King Martanda Varma in Kerala was the Dutch.

The rise of the Dutch in Kerala can be traced back to the early 17th century when they established trading posts in various parts of India, including Kerala. They were primarily interested in the lucrative spice trade and had set up a strong presence in the region.

King Martanda Varma, also known as Marthanda Varma, was the ruler of the Kingdom of Travancore in Kerala during the mid-18th century. He is often considered one of the greatest rulers in the history of Kerala.

Under his rule, the Kingdom of Travancore experienced significant expansion and consolidation of power. King Martanda Varma recognized the threat posed by the Dutch to his kingdom and embarked on a campaign to defeat them and regain control over the region.

- King Martanda Varma's Strategy

King Martanda Varma employed a combination of military tactics and political strategies to defeat the Dutch. His military strategy included forming alliances with neighboring kingdoms and building a strong army.

- Formation of alliances: King Martanda Varma formed alliances with the neighboring kingdoms of Cochin and Thekkumkoor. These alliances helped in pooling resources and strengthening the overall military power against the Dutch.

- Building a strong army: King Martanda Varma invested in building a well-trained and disciplined army. He modernized the army by introducing European-style training and equipping them with advanced weaponry.

- The Battle of Colachel: The decisive battle between the Kingdom of Travancore and the Dutch took place in 1741 at Colachel. King Martanda Varma led his forces to a resounding victory, defeating the Dutch and ending their dominance in the region.

The defeat of the Dutch at the Battle of Colachel marked a significant turning point in the history of Kerala. It not only established the supremacy of the Kingdom of Travancore but also weakened the presence of European powers in the region.

King Martanda Varma's victory over the Dutch solidified his position as a powerful ruler and laid the foundation for the subsequent expansion of the Kingdom of Travancore. His reign brought stability, prosperity, and cultural advancements to the region, leaving a lasting impact on the history of Kerala.