Complex sentence: Dating back to the period of Thretha yuga, while in exile Rama, Seetha and Laxmana were said to have come here and Laxmana's arrow pierced the rock to get water for Seetha, who was extremely thirsty.
Split into simpler sentences: Dating back to the period of Thretha yuga, while in exile Rama, Seetha and Laxmana were said to have come there. Laxmana used an arrow to make a hole in the rock in order to get water for Seetha, who was extremely thirsty.