Samaskuta kingdom was a kingdom located in inland Sumatra, Lake Singkarak in West Sumatra precisely at this time. There is not much history about the beginning of the establishment of this kingdom . But the kingdom is known to have existed before the eruption of Krakatoa in the 5th century. In the book of Ancient Nusantara (now Indonesia) King Serat Pustaka Raja mention the name of the king who ruled in the Kingdom Samaskuta in the year 416 AD is Prabhava Sangkalaid=1121.
References
Samaskuta Kingdom Wikipedia(Text) CC BY-SA