Su Song
With powerful sinicized kingdoms to its north such as the Tangut-led Western Xia, the Song dynasty was forced to engage in skillful diplomacy. The famous statesmen and scientists Shen Kuo (1031–1095) and Su Song (1020–1101) were both sent as Song ambassadors to the Liao dynasty in order to settle border disputes. Shen Kuo asserted the Song dynasty's rightful borders in the north by dredging up old archived court documents and signed agreements between the Song and Liao dynasties. Su Song asserted the Song dynasty's rightful borders in a similar way, only he used his extensive knowledge of cartography and maps to solve a heated border dispute.