The House of Austria

Through an amazing study of historical genetics, it has been confirmed that the Spanish Habsburg Dynasty—also known as the House of Austria—bred their own blood line out of the history books. As a result of repeated consanguineous (related by blood) marriages, one of the sovereign dynasties of Europe came to an abrupt end with the passing of Charles II of Spain. With Charles’ death on November 1, 1700, an entire line of Spanish Habsburg kings passed with him.

Charles II of Spain

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Charles II of Spain: the last Habsburg King

When Charles II died, he was physically disabled, mentally retarded, and disfigured. He had a tongue so large that it was difficult for him to speak or be understood. Completely bald at the age of 35, Charles died impotent, senile, and burdened with epileptic seizures. Based on centuries of genealogical records of the Spanish Habsburg family, this is what can happen following 16 generations of inbreeding.

Intermarrying to Preserve Their Pedigree

Spain reached the height of its power in Europe under Spanish Habsburg rule. In order to maintain their royal heritage, the Spanish Habsburgs began to intermarry among themselves. For approximately 200 years, most of their marriages were between blood relatives, including first cousins and uncles and nieces. For instance, Charles’ mother was his father’s niece—and his grandmother was also his aunt.

Charle's father Philip IV, who married his niece

Charle’s father Philip IV, who married his niece

If a child’s parents are closely related, the odds that they will be dealt unhealthy genes are greatly increased. Newborns inherit one set of genes from their father and another set of genes from their mother. Some genes will inevitably be defective, but odds are that a second, healthy set will replace those genes that are unhealthy. When parents are close relatives, they already share many of the same defective genes. The passing down of 2 sets of “problem genes” to a child can lead to genetic defects such as those found in Charles II.

Three Uncle-Niece Marriages of the Spanish Habsburgs

Philip II married Anna of Austria, daughter of his sister Marie

Archduke Charles II of Austria-Innerösterreich married Maria Anna of Bavaria, daughter of his sister Anna of Austria

Philipp IV married Marianna of Austria, daughter of his sister Maria Anna

Spanish Royal Inbreeding Continued Beyond Charles II

Infanta Maria Amalia (Carlos IV’s daughter) married her uncle Infante Antonio in 1779

King Fernando VII married his niece Infanta Isabel of Portugal (daughter of his sister Carlota Joaquina) in 1816

Once again, King Fernando VII married his niece Princess Maria Cristina (daughter of his sister Maria Isabel) in 1829

Infante Carlos, Count of Molina, married his niece Infanta Maria Francisca of Portugal (daughter of his sister Carlota Joaquina) in 1816

Infante Carlos married his niece and sister-in-law Infanta Teresa of Portugal (another daughter of his sister Carlota Joaquina, and sister of the above-mentioned Isabel and Maria Francisca) in 1838

Infante Francisco de Paula (brother of Fernando VII) married his niece Princess Luisa Carlotta (daughter of his sister Isabel) in 1819

Francisco de Paula and Luisa’s son, Francisco de Asis, married Fernando and Maria Cristina’s daughter, Queen Isabel II, in 1846

We all carry genes that may be defective. These defective or recessive genes do not normally become prevalent unless 2 closely related family members have children. Clearly, consanguineous marrying over generations within a large nuclear family can have a disastrous impact. For the influential and powerful Spanish Hapsburgs —a “dynasty of kings”—that impact was historic.

Next in the series: The English Royals


  1. Alvarez G, Ceballos FC, Quinteiro C. The role of inbreeding in the extinction of a European royal dynasty. PLoS One. 2009;4(4):e5174. %3Adoi%2F10.1371%2Fjournal.pone.0005174;jsessionid=58F0D5FF5EF3FD67F047CCA158AEBB6D.
  2. Cossins D. Did inbreeding royals Eevolve? TheScientist website. April 22, 2013.
  3. Inbreeding of Spanish royalty. GeneologyInTIme website. NewsStories/2009/April/inbreeding_of_spanish_royalty_page1.html.
  4. Yong E. How inbreeding killed off a line of kings. ScienceBlogs website. April 14, 2009.