After the first King Sena, the eldest son of Kashyapa Adipada, Prince Sena (853–887) ascended the throne. He is the king referred to as Dewanna in some records. The Pujavaliya and Nikaya Sangrahaya identify this king as Mugayin Vesisen. Prince Sena initially ruled the southern region as the first Mahadhipa. After the king’s death, he came to the capital, conducted the final rites for the deceased king, and was crowned. According to the Mahavamsa, he was a person endowed with great courage, heroic bravery, distinguished fame, and devotion. His consort was Princess Sangha, daughter of Kittu Agbo, the ruler of Ruhuna. She initially received the royal title of queen. Later, she was again given a coronation as the chief queen here. Hence, in chronicles, she is referred to as the queen twice, and in inscriptions, she is mentioned as Debiseva.

The king entrusted the rule of the southern region to his brother, Prince Mahinda, and crowned him as sub-king. However, fearing an incident in the inner palace, he fled to the Malaya country with his children.

During the events mentioned above, the king’s consort, Queen Sangha, had a child. The king, having imagined a noble prince, named him Kashyapa and gave him the Mahadhipa title along with the position of sub-king. At this time, Prince Mihindu, who had fled to the Malaya country, did not cause any conflict. He devised a method to remain allied with the king. Since the king’s son was given the position of sub-king, Prince Mahinda was unsettled. Therefore, he preferred to maintain friendship with the king rather than create disputes. When Prince Kashyapa held the title of Crown Prince, his minor paternal relatives inherited the same title and used it. This had never happened before. It appears that the king gave special attention to his son by bestowing the title of Crown Prince and that he carried it throughout his reign.

To maintain friendship with the king, Prince Mahinda received support from his other brother residing in Anuradhapura. He went to the king along with a group of monks belonging to three Nikayas and established a peaceful agreement. The monks acted as advisors to both Prince Mahinda and the king.

Maintaining peace among the brothers was for the welfare of both the princes and the people. It is evident that prior kings had caused the people suffering due to wars arising from royal disputes and greed. Furthermore, due to the deaths of Sinhalese and invasions from Tamil forces from southern India, the country faced significant danger. Therefore, the princes avoided conflict for the general welfare.

Prince Mihindu’s consort was named Tissa, who had a daughter named Sangha. He had another consort named Kitti. He had four sons and one daughter. It is evident that King Sena wisely ensured no conflict arose with Prince Mihindu. He entrusted Princess Sangha, daughter of Prince Mahinda, to his son, Prince Kashyapa, for safety. Before executing this task, the king discussed the matter with his ministers. Hence, if there had been any rivalry between Prince Mihindu and Prince Kashyapa regarding similar positions, it was neutralized.

Later, the southern region was handed over to his brother, and the king provided separate resources to his son. This collaboration strengthened the royal family. According to the Mahavamsa, they had many sons. Prince Mihindu, the sub-king, died in the thirty-third year of his reign, leaving the southern region vacant. The king appointed his son, Prince Udaya, to govern it.

The most significant event during the reign of the first King Sena was the war with the Pandya country. The Mahavamsa describes this incident as follows: One day, the king conducted a Dalada puja and went to the Ratna Prasadaya. He noticed that the seat where the golden Buddha statue was placed was empty. The ministers explained that your father, the former king, had come here, destroyed this island, and taken all valuables.

The king considered this an affront and decided to remove the humiliation suffered by his lineage. With pride, he prepared to attack the Pandya country and ordered the commander to do so. The purpose of mentioning the attack on the Pandya country is unclear. It is unlikely that Prince Sena, who was in Anuradhapura, was unaware of the invasions and looting during his father’s time. Upon seeing the empty Ratna Prasadaya, he must have recalled the invasion. The ministers confirmed this.

Meanwhile, the king received another occasion to invade the Pandya country: a Pandya prince, driven away by his father, came to Sri Lanka seeking help to claim the throne. The king received him, organized a military campaign from Mahatiththa, and instructed the commander to capture the Pandya country, enthrone the prince, and return all valuables taken from the country.

The Pandya prince who came to Sri Lanka was Sri Mara Sri Vallabha Pandya’s son. He had come against his father. Before the battle, King Sena made an agreement with Pallava King Nrupatunga. Therefore, the Pallavas from the north and Sinhalese from the south were involved in the attack on the Pandya country. Sri Mara Sri Vallabha fought against the Pallavas from the north but suffered a significant defeat at a place called Arichin.

The Sinhala army, led by Commander Kutthaka, destroyed villages and surrounded Madurapura, the Pandya capital. When the city was captured and the Pandya army defeated, Sri Mara Sri Vallabha retreated north. However, he could not face the Sinhalese. During the battle to secure the kingdom from the Sinhalese, Sri Mara Sri Vallabha died. The Sinhala army completely looted the city, and the valuables brought by Sri Mara Sri Vallabha from Lanka, as well as treasures from the Pandya palace, were brought to Sri Lanka. By sacrificing his life in this manner, the heroic Sinhalese received recompense for the Pandya invasions.

Commander Kutthaka, as the king’s representative, enthroned the second Pandya prince in India under the Sinhala king’s authority. After this, Kutthaka returned to Lanka. The king gave respect to both the commander and the army. The conquest of the Pandya country by King Sena is confirmed in many inscriptions. In one inscription from Iripinniya, the commander is mentioned as Kuttha Senewira.

King Sena conducted many religious activities according to precedent. The golden Buddha statue taken by the Pandya king from Ratna Prasadaya was restored by Kuttha Senewira. Anticipating future attacks, the king organized protection and secured the country fearlessly. According to the Mahavamsa, he also developed the northern regions of the island. He is described as a king who provided gifts to Brahmins. The Nikaya Sangrahaya notes that the victory banner taken by the Pandyas was recovered and returned to its place. Monks carried out many religious activities, including temple construction, renovation, and maintenance. Sutras were written, and the Buddha’s images were paraded around the city while the Mahasangha chanted, which alleviated the fear of disease, as recorded in the Mahavamsa. This indicates there was some epidemic, though no other records mention it. Reading of the Abhidharma was also the king’s pastime. The coronation at Ruwanwelisaya was conducted and celebrated for one year as a ritual.

Not only the king but also his queen Sangha, Kutthaka Senewira, and Crown Prince Mahinda developed temples under the king’s guidance. The temples developed by Mihindu were named Sena Mahinda, those by the queen Sangha as Sena Sangha, and those by Senewira as Sena Senapati. The use of the name "Sena" in all three cases was to honor the king.

King Sena was also mindful of economic development. Maintaining peace, rebuilding what had been destroyed by enemies, and strengthening the economy were part of his work. He constructed a large canal in the Mahaweli River called Manimebala. This was the first large-scale effort to use the Mahaweli River for national development. Previously, King Dhatusena had made a small canal, but it was not as notable. He also constructed the Minneri tank, connecting Katunnaru and Kana canals. Kana Wapi is believed to be the modern Mihinthalaya area.

From an epigraphical perspective, some disturbances occurred during his reign, as mentioned in the Nikaya Sangrahaya. During King Matuwala Sena’s time, the Vajiriya Vadiya, a Vaidhulya Dharma, was introduced to the country. It was brought by a monk from the Dambadiva Vajraparvata Nikaya, which was accepted by King Matuwala Sena. The second King Sena spread the Dhamma of three Nikayas, protecting relics and ensuring the guardianship of Lankans. However, the Mahavamsa mentions that some Panchukula monks left Abhayagiriya. This is only a hint. Some words in the chronicles, like Gatahessuṅ, are questionable, and may refer to division among monk groups. More than thirty inscriptions from King Sena’s reign have been found across the island, showing his authority was recognized everywhere, even reaching the Pandya country. In these inscriptions, the king’s name appears as "Abhaya Sirisagabo Mapurmuka Sirisagabo Rappa," among other forms. Many inscriptions provide details about donated lands, administration, and governance. From them, some aspects of King Sena’s administrative methods can be understood.

An inscription near Mamaduwa tank in Vavuniya was established in the thirty-third year of King Sena’s reign. The tank is called Mahida Wewa (Mahinda Wapi). The official mentioned is Manamathu Dehimiya, believed to be the present-day area near Velgamwehera in Trincomalee. If he was the administrator, his authority extended to the northeastern and northern regions. The inscription refers to threats to villages and forbidding fishing in the tank. Some tanks prohibited fishing at this time. The inscription states that if villagers caught fish, the local official, called Gamladda, would confiscate ten gold coins for the Madambiya Vihara’s activities. Gamladda acted as the local law enforcer, similar to a modern municipal officer. Other officials also violated the law, as indicated here. Another inscription from the Abhayagiriya area of Anuradhapura forbade fishing in tanks, marking boundaries with embankments. This is a second inscription of King Sena.

Another inscription near Medavachchi at Kongollawa details land grants to Kukulgiri Petha (Tukku Giri Vihara) at Abhayagiriya and administrative procedures. A water source dedicated to a village north of the city is also mentioned. The king’s name here is recorded as "Madhura Pahala Sirisagboḍhi Rajapa." The inscription indicates the conquest of Madura Pur by the second King Sena. Another inscription from Illuppakanniya mentions Madhura Pur’s conquest. An inscription near Kaegalu shows the king’s thirty-third year and the Maliva Arama temple with two annual objectives. Maliva Arama is identified as the Selawa Rajamaha Vihara today. The king’s last inscription is at Nachchaduwa and is a personal inscription. King Sena ruled for thirty-five years.