Mathematics is often perceived as an abstract discipline remote from historical inquiry. This paper challenges that notion by demonstrating how mathematical methods—ranging from statistical inference and network analysis to dynamical systems and spatial modeling—have transformed historical research into a predictive, evidence-based tool for societal benefit. We present three case studies: (1) using time-series econometrics to identify early warning signals of civilizational collapse, (2) applying network theory to map ancient trade routes for modern economic resilience, and (3) employing geospatial statistics to optimize cultural heritage preservation under climate change. The findings show that mathematically informed history not only corrects narrative biases but also provides quantifiable guidance for contemporary policy. This paper argues that integrating mathematics into historical science delivers 100% practical utility to society by turning the past into a computable laboratory for future decision-making.