Abstract
Inbreeding and the Fall of the Spanish Habsburg Dynasty examines how centuries of consanguineous marriages within the Spanish Habsburg family contributed to the dynasty’s decline and eventual extinction. Focusing on the reign and health of Carlos II of Spain, this study explores how dynastic marriage strategies, which were designed to consolidate political power and preserve royal lineage, ultimately produced severe genetic consequences. This thesis analyzes patterns of intermarriage beginning with Carlos I and continuing through the next four monarchs, highlighting the repeated marriages between close relatives. These practices significantly increased the likelihood of inheriting harmful recessive traits. In addition, this study examines the role of religious law and papal dispensations in legitimizing these unions, demonstrating how political priorities often overrode restrictions in canon law. Drawing on historical accounts and modern genetic research, this paper establishes a clear connection between prolonged inbreeding, consanguineous marriages, and elevated rates of physical deformities, intellectual disabilities, infertility, and high infant mortality rates within the dynasty. The condition of Carlos II serves as the most extreme example of these effects. Ultimately, this thesis argues that the Spanish Habsburg’s reliance on consanguineous marriage as a political strategy produced long-term biological consequences that weakened the monarchy and contributed directly to its collapse in 1700.
Semester/Year of Award
Spring 5-2-2026
Mentor
David, Coleman
Mentor Department Affiliation
History
Access Options
Open Access Thesis
Document Type
Bachelor Thesis
Degree Name
Honors Scholars
Degree Level
Bachelors
Department
Nursing
Recommended Citation
Kent, Kira L., "Inbreeding and the Fall of the Spanish Habsburg Dynasty" (2026). Honors Theses. 1164.
https://encompass.eku.edu/honors_theses/1164
