Answer
Key negotiator, Tomás Domínguez Arévalo played a pivotal role in Carlism, a Spanish political movement that supported the Carlist pretenders to the Spanish throne. As a skilled negotiator, Arévalo was instrumental in forging alliances and brokering agreements between various Carlist factions, helping to unify the movement and advance its goals. His diplomatic efforts were crucial in shaping the course of Carlism and its impact on Spanish politics.