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The seeds for the war were laid when the Raja of Travancore began expanding his small kingdom by entering into territorial disputes with his neighbours, the Kingdoms of Kayamkulam and Kollam in 1731. These disputes began impacting the Dutch East India Company since they had factories for exporting pepper in these areas, collectively known as Dutch Malabar.
The destruction of crops in the war made it difficult for the Kollam merchants to fulfill their agreements with the Dutch. By 1733, VOC pepper exports dropped to less than half the quantities of 1730-31.
To help the three Kingdoms mediate the VOC deputed their emissaries, William Feling, Abraham Van De Welle, Ezechiel Rhabbi and Brouwer to Kayamkulam in May, 1734 to negotiate with the Raja, though they were unsuccessful.
The annexation of Eleyadathu Swarupam, the largest pepper producing area in southern Kerala, by the Raja during 1737 made a confrontation between him and the VOC inevitable. The advent of British traders in this market also made the price of pepper soar. All of this forced the VOC to engage the Raja and thus began, in 1739, the Travancore–Dutch war that led to the Battle of Colachel.
Marthanda Varma crushed the opposition to his rule in his State and then absorbed the kingdom of Attingal. His next target was Quilon whose ruler Unni Kerala Varma was an ally of Kayamkulam. The Kayamkulam Raja formed an alliance with the rulers of Cochin, Purakkad and Vadakkumkur against Marthanda Varma. In AD 1734, the ruler of Kayamkulam was killed in battle. Marthanda Varma moved against Kottarakara. In AD 1739, Marthanda Varma refused to recognise the claim of the senior princess of the Kottarakara family to the succession, following the death of the chief of the Elayadathu Swarupam. She in turn, appealed to the Dutch East India Company. The Dutch were unhappy with the annexation of the kingdoms of their allies and a meeting between Marthanda Varma and the Dutch factor Van Imhoff aggravated the situation with Van Imhoff threatening to attack Venad and Marthanda Varma threatening to carry war into Dutch territories. In 1741, the Dutch formally installed the princess as the ruler of Kottarakara. A combined Kottarakara-Dutch army was decisively defeated by Marthanda Varma's army and the state of Kottarakara was annexed.
Marthanda Varma then captured the Dutch forts in the vicinity. A Dutch force under the command of De Lennoy landed at Colachel from Cochin and captured the country up to Kottar. Marthanda Varma marched south and prevented the capture of Kalkulam by the Dutch. When the Dutch retreated to their base in Colachel, Marthanda Varma pursued them and caught up with them on the 10th of August, 1741. In the battle of Colachel Marthanda Varma won a decisive victory over the Dutch and captured 24 officers including the commander De Lennoy. A pillar of victory which gives details about the war still stands near the coast of Colachel. There are some folk tales among the local Mukkuvar people about this war. The tale says among other things that the local Mukkuvar fishermen were asked to stand along the beach in multiple rows with their oars kept along the shoulders so that it would appear like soldiers standing with their guns. They were also instructed to make fake cannons as a diversion. The local fishermen, who were all Roman Catholics (converted in the 16th century en-masse) cooperated extensively with the Raja's guards during this war.
The Dutch then concentrated their attention on Quilon and the combined Quilon-Kayamkulam-Dutch army seized Vamanpuram. The Venad army under Ramayyan Dalawa chased them out of Vamanapuram and besieged them in the Quilon fort. The Kayamkulam minister Achutha Warrier led the successful defence, forcing the Venad army to retreat and even occupying Kilimanur in 1742. Marthanda Varma himself took charge and divided the Venad army in three squadrons, led by prince Rama Varma, Ramayyan Dalawa and De Lennoy. The allies were crushed in battle and forced to retreat to Quilon. The Venad army then moved toward Kayamkulam and the Raja of Kayamkulam sued for peace and signed the treaty of Mannar in 1742.
However, to extricate himself out of the situation, the raja of Kayamkulam allied himself with Vadakkumkur, Thekkukkur and Purakkad and violated the treaty obligations. The Venad army occupied Kayamkulam in 1746 and the alliance of the Kayamkulam raja gave Marthanda Varma a casus belli against the allies. The Ambalapuzha army led by Mathur Panikkar and Tekkedathu Bhattatiri deserted to the Venad army, and Marthanda Varma captured the State. In 1749 and 1750, Tkekkumkur and Varakkumkur were annexed. Following these developments, the Dutch signed the treaty of Mavelikkara in 1753 with Marthanda Varma whereby they undertook a strict policy of non-intervention and repudiated their alliances with other Kerala powers.
In 1753, the northern parts of the newly created state of Travancore rebelled under the influences of the exiled rajas of Ambalapuzha, Thekkumkur and Vadakkumkur. The rebels were aided by the maharaja of Cochin and the Dutch and their army was commanded by Palliyil Idikkela Menon, a courtier of the maharaja of Cochin. Towards the end of 1753, the Cochin army occupied Purakkad. On the 3rd of January 1754, the rebels, backed by the armies of Cochin and the Dutch, met the Travancore forces led by prince Rama Varma, Ramayyan Dalawa and De Lennoy in the battle of Anadeswaram. Even though the battle was tactically a stalemate, it was a strategic victory for Travancore, since the allies were forced to withdraw to Ambalapuzha. In the battle of Ambalapuzha, the allies were decisively defeated and a large number of Cochin nobility were killed or captured. The allied commander Idikkela Menon was captured and executed. The Travancore forces captured all of the Cochin territories up to Arukutti, Udayamperur in the south and Mamala in the east. The Cochin raja sued for peace and in 1757, under the auspices of the Dutch and the prime minister of Cochin, Paliath Komi Achan a peace treaty was signed.
The Travancore-Dutch relations improved after the Dutch sold the Cranganore and Pallipuram forts to Travancore, which were incorporated into the Travancore lines (Nedumkotta).