Typology of ancient grave markers in the Siak Sultanate: tracing history, regional interactions and Islamic symbolism in Riau, Indonesia

The Siak Sultanate was an influential power on the east coast of Sumatra during the eighteenth and nineteenth centuries. In its former capital, centred on the modern city of Siak, Riau, Indonesia, the tombs of the Sultanate’s families are marked by monuments of unique and highly varied forms. However, these markers have not been comprehensively studied. This study aims to present the types of ancient Islamic tombstones and trace their origins to reveal the cultural interactions of the Siak Sultanate with other regions in the past. A total of 85 ancient tombstones spread across 10 sites were systematically documented as the primary data in this study. We used a mixed quantitative and qualitative analytical method. The results indicate that the diversity of grave markers in the Siak Sultanate (eighteenth–twentieth centuries AD) was influenced by regional, political and cultural interactions in the Malacca Strait region for 200 years. The statistical results show significant associations between grave-marker typology and material, chronological period, and decorative attributes (p < 0.001). This study also proposes a methodological framework applicable to comparative studies in other regions of maritime Southeast Asia. This research opens up new opportunities to utilize grave markers as tools for tracing changes in trade networks, cultural interactions and power dynamics in the region.