They told him that they would conduct such a sacrifice on the Pūrṇimā of the month Caitra.

NOTE. It should be noted that all of the fire sacrifices mentioned in the Vedic literature gradually help a person become self-realized and then finally achieve realization of the Supreme Personality of Godhead. Therefore, the brāhmaṇas were happy with King Daśaratha’s desire to perform the Aśvamedha sacrifice.

Śrīla Prabhupāda states the goal of these sacrifices in his purport to Bhagavad-gītā 2.46: “The rituals and sacrifices mentioned in the karma-kāṇḍa division of the Vedic literature are meant to encourage gradual development of self-realization. And the purpose of self-realization is clearly stated in the Fifteenth Chapter of the Bhagavad-gītā (15.15): the purpose of studying the Vedas is to know Lord Kṛṣṇa, the primeval cause of everything.”