The assumption of the Carlist claim to the Spanish throne by the childless octogenarian Alfonso Carlos in 1931 created an acute and barely soluble problem regarding the Carlist succession. Involved in the tortuous debates on the subject were varying interpretations of the Salic Law, as well as of the so-called ‘principle of dual legitimacy’, whereby a Carlist claimant, and ipso facto a legitimate king of Spain, must accept the postulates of Traditionalism and behave in conformity with them as well as being legitimate in terms of blood. The following is an attempt briefly to clarify a question about which whole books have been written. Attention is drawn to the accompanying genealogical table.

The Alfonsist claim

The Alfonsist claim to ‘succeed’ Alfonso Carlos as Carlist claimant was paradoxically based upon that same strict interpretation of the Salic Law which the Carlists had originally used in their attempts to exclude Isabella II. Thus viewed, even assuming the Carlist claim to have been valid, the claim reverted upon the extinction of the Carlist male line to the direct descendants of Francisco de Paula, younger brother of Ferdinand VII and Carlos V. Since Francisco de Paula's eldest son, Francisco de Asís, had married Isabella II, these descendants were none other than the Alfonsine branch.

Although this argument was genealogically sound, Carlist critics opposed it on the grounds that both the Isabelline and De Paula branches of the Spanish Bourbons were permanently disqualified from the succession as a punishment for their past liberalism; a further black mark against Alfonso XIII and his sons was the highly doubtful paternity of Alfonso XII, which placed in question their very descent from Francisco de Paula.