@mythandlegend I just looked up this information on the Internet and the following is what I found:
The Legend of Roro Jonggrang is basically what this is about. It is a story of love and betrayal, the warrior and the cursed princess.
It also explains the mythical origin of the Ratu Boko palace, Sewu temple, and the Durga statue in the Prambanan temple compound.
The title Roro is an ancient honorific title to address unmarried princesses and female nobility, thus the name Rara Jonggrang in Javanese means 'slender maiden'.
The legend tells the story of two ancient and neighbouring kingdoms in Java, Pengging, and Boko.
Pengging was prosperous, and wisely ruled by its King Prabu Damar Moyo. He had a son named Prince Bandung Bondowoso.By contrast, Boko was ruled by a cruel man-eating giant named Prabu Boko. Despite his unpleasant nature, Prabu Boko had a beautiful daughter named Roro Jonggrang.
In short, Prabu Boko desired to expand his kingdom, and so began training an army and raising taxes for an invasion of Pengging. His forces launched a surprise attack on Pengging, and the ensuing war caused devastation and famine on both sides. To defeat the invader, Prabu Damar Moyo sent his son Bandung Bondowoso to fight Prabu Boko. After a furious battle, Prabu Boko is killed by the prince's supernatural powers. Then the Prince sets his eyes on the beautiful princess, & pleads to have her marry him. She refuses, until she comes up with a plan. The prince must build so many structures in one day to show how deeply he loves her. However, during the Prince's building, the Princess came up with deceitful tricks to kill him, but to her astonishment, his superpowers were able to thwart her foolishness. After, he found out about her antics, he placed a curse on her and turned her into stone. In this way she became a feature of the final temple, completing its construction and fulfilling the conditions for their union.