Who supported Don Carlos during the Carlist Wars in Spain?

During the Carlist Wars, support for Don Carlos and the Carlism movement was primarily rooted in rural traditionalism, which stood in stark opposition to the urban liberalism of the Isabelline government.1

Key supporters and sources of strength included:

• Regional Interests: The movement found its strongest support in the north of Spain, particularly in the Basque provinces and Navarre. These regions supported Don Carlos largely to defend their local fueros (traditional legal privileges) against the encroachment of liberal centralism.1
• Conservative and Clerical Factions: Carlism originated from the apostólico or extreme clerical party. Supporters were deeply committed to the traditional Roman Catholic order and opposed the secularizing and liberal reforms of the era.21
• Royalist Volunteers: The movement was mobilized as early as 1827 through paramilitary groups known as Royalist Volunteers, who formed the backbone of the opposition to liberal governance.2

While the Carlists maintained a dedicated base, they struggled to expand their influence beyond these rural strongholds, ultimately failing to capture major urban centers during the conflicts.1