MADRID They once helped conquer an empire on which the sun never set but now members of the Spanish aristocracy are engaging in a more prosaic struggle over whether their titles should be inherited by women.

A group of grandees and other nobles have rebelled against a recent change in Spain's law, which prevents a son from claiming the family title if he has an elder sister. They are demanding the country's constitutional court strike the law down as it may allow some women to claim titles retroactively, taking them from brothers or uncles who currently hold them.

They claim the law was tailor-made to suit a group of powerful women, including the designer Agatha Ruiz de la Prada, who claimed titles held by male relatives. Ruiz de la Prada claims the title of Marquess of Castelldosrius from an uncle who received it from his elder brother - skipping Ruiz de La Prada's now deceased mother.

“The law should not be retroactive. There will be fights in all the noble families because of this,” said Miguel Temboury of the Spanish Nobles Association, a recently created conservative faction within Spain's 2,500-strong nobility.

They say Ruiz de la Prada and her partner, the El Mundo newspaper editor Pedro J Ramirez, used their influence with Jose Luis Rodriguez Zapatero's socialist government to make the law retroactive.

Under the terms of the new law those like Ruiz de la Prada, who had already brought legal cases against current holders of titles, are able to pursue their claims.

The new law was introduced after Spain's highest courts ruled in favour of male primogeniture, despite attempts by a group of some 20 women to have it banned for contravening sex equality laws.

Zapatero's party brokered a cross-party agreement to change the law two years ago. A number of court cases are being fought between siblings for the family title.—Dawn/Guardian News Service