King Dhatusena unfortunately was put to death, and the throne was taken over by Prince Kashyapa (477–495). He is recognized as the first king known by that name and, because he built Sigiriya, modern scholars also refer to him as King Kashyapa of Sigiriya.

The Mahavamsa clearly describes the actions of the commander who incited Prince Kashyapa to kill his father. King Dhatusena’s daughter was entrusted to the commander’s care. One day, the commander assaulted her with a ceremonial weapon. Seeing his daughter with torn clothes, the king severely punished the commander’s mother. Some say she was beaten to death, but the Mahavamsa does not mention any execution, only that she was flogged; perhaps only a part of her body was punished. The king showed deep affection for his daughter. By familial relation, the commander’s mother was the king’s sister. Because of the severe punishment, the commander became hostile toward the king.

Therefore, motivated by resentment toward King Dhatusena, the commander could not inherit the kingdom himself, and he incited Prince Kashyapa to do so. Kashyapa, not looking far ahead, seized the opportunity, ascended the throne, and later ordered the death of his father.

The process unfolded as follows: The commander, having devised a method to kill the king, reported to King Kashyapa that King Dhatusena would keep his wealth for Prince Mogallana. Upon hearing this, King Kashyapa questioned his father. Dhatusena said, “If my wealth goes to the reservoir, inform me.” To claim the wealth, King Dhatusena was sent under protection to the Kalavapi reservoir by Prince Kashyapa. There, the king went to the Kalavapi temple, engaged in a discussion with the monks, and allowed the wealth to be deposited in the reservoir to show the nobles. When the royal nobles learned all this, Prince Kashyapa, filled with enmity, entrusted the commander with the task of destroying the king. Dhatusena’s demise followed.

Under these circumstances, Prince Mogallana could not intervene and fled to India. King Kashyapa was fully aware that in the future he would face the influence of Prince Mogallana. He sent assassins to India, but this attempt failed. He was thus haunted by two fears: the guilt of patricide and the certainty that Prince Mogallana, as the rightful heir, could appear at any moment. Fearing this, Kashyapa abandoned Anuradhapura and moved to the fortress of Sigiriya, about forty-seven leagues to the south, which was difficult to access.

The Mahavamsa states:
"That wicked tyrant, Kashyapa, failed to kill his brother due to fear. He fortified Sigiriya, inaccessible to humans, surrounded it with walls in a lion-shaped design, constructed magnificent palaces with stairways, and deposited wealth, appointing guards to ensure security."

From this description, the reasons for building and residing at Sigiriya, its structure, and the king’s other intentions become clear. Like the Mirror Wall at the Alakamandava, King Kashyapa of Sigiriya, like the king of Alakamandava, shone in his magnificence. Sigiriya was a fortress, not a palace offering proper protection; surrounded by enemy forces, no one inside could be guaranteed safety. Within a few days without food or water, one would face death.

The Mahasangha in Anuradhapura and many townspeople did not support King Kashyapa. The psychological weight of killing his father notwithstanding, living far from the general populace and Sangha ensured a relatively safer existence. The Sigiriya rock is about forty-seven leagues from Anuradhapura and approximately 600 feet high from the base. The summit covers about three acres, containing the king’s palace and other necessary buildings. The surrounding land protected by walls measures more than a hundred acres. The eastern wall is rectangular, the western similarly rectangular. The eastern steps were about one cubit wide, though the western fortifications had three ramparts, two of which are still visible.

The fort had five gates; the main one was on the western side, with two smaller gates to the north and south. The western entrance leads to three terraced gardens:

1. The first is a rectangular area about 300×396 feet, with walls five feet high, accessible through the western gate.

2. The second is a water garden, about 528×78 feet, with two levels and complex water channels.

3. The third is a rock garden with eight pools, surrounded by rugged rocks, with carved stone faces.

These gardens show sophisticated landscaping, with evidence of artistry on the rocks. The Sigiriya rock also contains inscriptions and murals, indicating it was a Buddhist monastery in the pre-Christian era. The western fortifications have galleries, stairways, and numerous intricate designs, including a “Broken Stone Wall,” named after a cracked stone used in construction.

The main path from the western gate divides into various routes, leading to a lion figure at the base. From there, steep steps ascend to the summit. Originally, the lion figure was complete, but now only the paws remain. This lion gave Sigiriya its modern name, and it was designed majestically.

On the western fortifications, the main path runs parallel to walls and a broken stone wall. Steps are meticulously constructed on the natural rock, leveling surfaces with stones to form a climbable path. Poetry carved along the route was created later, after King Kashyapa’s time, by visitors.

The western gate leads to a cliffside cave with murals known as the Sigiriya frescoes. Originally, there were about fifty frescoes, now only nineteen remain; some were destroyed in modern times. The female figures depicted are known as the Sigiriya Apsaras, some portrayed in gold and blue, possibly representing clouds or lightning, according to scholars.

Other areas of Sigiriya, such as Mapagala (possibly named after a prince’s section) and Ramakela to the south, contain stupas, inscriptions, and remnants of buildings. The Mahānaga Pabbata Vihara, a monastery, is evidenced by inscriptions. The upper rock has a large cistern, presumably for religious offerings.

After ascending the throne, King Kashyapa engaged in many meritorious deeds to atone for his grave sins: cultivating mango gardens across the island, repairing irrigation systems, promoting meditation and moral development, compiling sermons, and constructing numerous shrines. He had two daughters, Bodhi and Uppalavanna. He restored the Isurumuni Vihara and dedicated the daughters’ names to the Mahavihara for worship.

The commander Migara is mentioned in the Mahavamsa; he did not participate in acts of filial rebellion against King Dhatusena and is distinct from the earlier commander who assisted in the king’s death. Thanks to King Dhatusena’s developmental projects, King Kashyapa was able to enjoy the resulting prosperity. Commercial relations with India and other countries flourished, with major ports like Mahatittha and Gonavampattana serving as trade centers. Roman coins found at Sigiriya indicate active international trade.

During King Kashyapa’s reign, his authority extended across the island. Even in Ruhuna, his rule was undisputed. Administrative records from nearby areas show governance under local ministers. Despite these dangers, King Kashyapa’s reign lasted about eighteen years.