According to the journals of the Portuguese explorer Tomé Pires between 1513 and 1515, Siak is an area that lies between "Arcat" and "Indragiri" which he calls a port city under a Minangkabau king, then became a Malacca vassal before being conquered by the Portuguese. Since the fall of Malacca into the hands of the Dutch East India Company (VOC), the Johor Sultanate has claimed Siak as part of its sovereignty territory. This continued until the arrival of Sultan Abdul Jalil Rahmat Shah or "Raja Kecil" who later founded the Siak Sultanate. In the "Syair Perang Siak", it is told that "Raja Kecil" was asked to become the ruler of Siak for the consensus of the people in Bengkalis. This aims to release Siak from the influence of the Johor Sultanate. While according to the "Hikayat Siak", "Raja Kecil" was also called the true inheritor of the throne of the Sultan of Johor who lost the power struggle. Based on the correspondence of the Sultan Indermasyah with the Dutch Governor-General in Malacca at that time, it was mentioned that Sultan Abdul Jalil was his brother who was sent for business affairs with the VOC. Sultan Abdul Jalil then wrote a letter addressed to the Dutch, calling himself the "Raja Kecil" of Pagaruyung, that he would take revenge for the death of the Sultan of Johor.