Abstract

This study presents an approach to date historical inscriptions by integrating modern astronomical computation with the Indian lunisolar calendar system. Focusing on the inscriptions associated with the Srivijaya Kingdom spanning the late seventh to the mid-fourteenth centuries, this study implements a computer program, which utilized differential equation approach to solve Kepler’s Transcendental Equation, to compute planetary positions and visualize them as astrological charts and planispheres. The identification of differences between ‘lapsed’ and ‘current’ Śaka year notations, which were used differently on the Thai–Malay Peninsula and Sumatra–Java, and the use of back-computed astronomical data to confirm the celestial positions recorded in the inscriptions, are two important findings. These results show how archaeoastronomical knowledge and its social uses have changed over time, underscoring the possibility of combining historical research methods with computational astronomy to enhance our knowledge of ancient societies through multidisciplinary investigations.