Complex sentence: Raghunatha Thondaiman was succeeded by his son Ramachandra Thondaiman (1839-1886) whose long tenure of office was marked by extravagance and gross mismanagement.
Split into simpler sentences: Raghunatha Thondaiman was succeeded by his son Ramachandra Thondaiman (1839-1886). His long tenure of office was marked by extravagance and gross mismanagement.