Date: 28th March 1638
The Portuguese had attempted three times without success to capture the Kingdom of Kandy, in order to bring the entire country under their rule. In 1635, King Rajasinghe II became the king of Kandy and started negotiations with the Dutch to obtain their help in driving out the Portuguese from the island. The Portuguese hastened their efforts to take Kandy because of this, and Diogo de Melo de Castro, the Portuguese Captain General, tried to provoke the King of Kandy on several occasions.
Melo seized an elephant presented to a merchant by the king, to which the king responded by seizing two of Melo's own horses. Following this incident, on March 19th 1638, Melo assembled a large army and set out for Kandy to destroy the Kingdom.
Rajasinghe sent a letter to Melo through a Portuguese friar seeking negotiations, but this call was rejected by Melo, who replied, saying "The little black is frightened. We shall drag him by the ears".
Instead of facing the Portuguese army head on directly, King Rajasinghe II and his generals planned a trap. The entire city was evacuated and everything of value was taken to the jungles.
The Portuguese force advanced through Atapitiya to Balana, a fort and observation post of the king's army.
When the Portuguese army finally reached Kandy, they found the city deserted. They sacked and burned the city, including the royal palace and temples, and then having thought they won this battle easily, started to withdraw back to Colombo.
As they were returning their path was blocked by huge trees and suddenly without any warning they were attacked by the Kandyan army who were hiding deep in the thick jungles.
The object of the Portuguese was to entrench themselves on the slopes of Kiriwaththalawa (present day Kiribathkumbura), but before they reached high ground they found themselves surrounded by the Kandyan forces. The King's army in full force awaited the return of the Portuguese at Gannoruwa.
When they reached Gannoruwa they found that crossing the river was made impossible by the Kandyans as they had cut down trees and obstructed the Portuguese path. The road back to Kandy was also blocked and all escape routes were effectively cut off.
Since there was no way of crossing the river or heading back to the city , the Portuguese army camped on top of a hill for the night.
Having had an exhausting day, the Portuguese army was tired and thirsty. Since the Kandyan army took guard of the River there was no way of drinking water without risking being killed by the skilled shooters camped at the base of the hill.
To make matters worse, the gun powder of the Portuguese were targeted by the King's army from a nearby mountain. It is said that "balls of fire" were hurled at the hill where the Portuguese army had camped, and throughout the night the Portuguese gun powder got burnt.
On the following day, the Portuguese force tried to resume their retreat but the Kandyan army at once attacked the Portuguese army and numbers of the Portuguese force were rapidly reduced as the Kandyan army charged up the hill and attacked them.
With the Portuguese force suffering heavy damages, Melo requested an armistice. Rajasinghe did not reply to this, but ordered his drummers to proclaim that all Sinhalese that were with the Portuguese force were to leave them. They were told that those who remained would be put to the sword the next day.
The entire Portuguese army was resolutely crushed and annihilated, and their heads were gathered to a ghastly pile like coconuts at the feet of the warrior King, who skilfully led his powerful armies to a thrilling triumph and saved the Sinhalese Kingdom from the subjugation to a alien European Power.
The main reason why the colonial forces couldn't fight with the Kandyans was their guerrilla warfare battle tactics.
Unlike the Portuguese, the Kandyans were familiar with leeches, monsoon rain and the terrain. They knew the land and the secret footpaths and successfully engaged in guerrilla warfare. They set up road blocks on the narrow winding paths; usually at a bend. They placed their guns between rocks and trees and launched surprise attacks. They regularly ambushed the Portuguese as they climbed the hills. They dropped felled trees and boulders on them and attacked the trapped soldiers.
The Portuguese did not make any other attempts to take Kandy after this.The Battle of Gannoruwa was the last battle fought between the Portuguese and the Kandyans. Rajasinghe eventually made an agreement with the Dutch and eventually the Portuguese were driven out of the country in 1658.