Indonesia, influence of our epics and of hinduism and buddhism.

We are told of a meeting the sultan of Demak called and sought ideas from walis (saints) to solve the problem of many mishaps, failed crops and the ensuing poverty which came in the way of Islam taking root.

In the meeting, a young wali, Sunan Kalijogo, with due respect seeking permission to speak said that while he prayed for guidance from Allah, he heard a voice, 'If you want the good fortune to return, restore the old traditions! Choose from the old culture elements that can be used to enrich the new.' And he then requested the elders with their wisdom explain to all what it meant. The message he put forward was not easy to read. A return to the old meant a return to hindusim and buddhism. Moreover idol worship was a great sin in islam.The elders kept silent and shook their heads.

With great hesitation the young wali, spoke again with caution, and said 'We have to admit that so far the drum in our mosque has made people deaf towards the teaching of islam, could we not place the gamelan beside the drum?'  The elders did not think it was a good idea, but the young wali managed to convince them with 'could we not read the name of allah on it and make it rightful for us?'  and suggested keeping it in a special place within the compound of the mosque. Similarly he suggested adaptions of certain hindu practices like uttering a mantra as they entered a temple and the practice of shraddha in an islamic way. He concluded, 'Let the old customs become the container, and the new elements of faith the content.'

Gamelan is said to predate even Hindu-Buddhist culture. The author says that it is only in Java that one would find musical instruments in a mosque. courtsey wikipedia.

It was not just the arguments that were placed, but it was the open mind that was prevalent in those days. The author Soewito Santoso says: This integration of old cultural elements and religion was one of  main reasons for the successful spread of islam in Java.