Kotte was originally founded as a fortress by Minister Alakesvara (1370–1385) of the Alagakkonara clan in the Kingdom of Gampola during the reign of Vikramabahu III of Gampola. It was built to counter invasions from South India along the western coast. In 1412, Parakramabahu VI established Kotte as his capital city. The site was naturally well protected by the extensive swamp that surrounded it.

Parakramabahu VI first became the king of Gampola in 1412, and in 1415, he established Kotte as his capital. He expanded and fortified the existing citadel and built a new royal palace. Parakramabahu VI waited until ties between the Vijayanagara Empire and Jaffna Kingdom were severed. First, he captured the Vanni and made its leaders loyal to him. Prince Sapumal was the commander of the Kotte army at the time. However, Kanakasooriya Cinkaiariyan and his two sons soon returned from Madurai with mercenaries and regained control of the Jaffna Kingdom, bringing it out of Kotte’s overlordship and reestablishing its independence.During this period, Tamil was used as one of the court languages of the Kotte Kingdom.