According to Geni.com, María del Pilar de la Cerda was born on 25 November 1876 and lived until 8 November 1931. If that is so, then this glamorously dressed person should be the previous Duchess of Veragua, Ramona Eugenia María Josefa Hurtado de Mendoza y Ruiz de Otazu, who lived between 16 November 1841 and 9 August 1915. The date in the lower right quadrant below Madrazo’s signature dates this portrait of a mature woman to the 1870s. I cannot absolutely resolve the final digit, but believe it is 1 (one).
According to Wikipedia, "Veragua or Veraguas was the name of five Spanish colonial territorial entities in Central America, beginning in the 16th century during the Spanish colonization of the Americas. The term was based on a Central American indigenous peoples name for the region. It was used for colonial territories in present-day Costa Rica, Nicaragua, and Panama..."
From pinterest.com/alucasfauchon/retratos-portraits/. A white strip was removed from the upper part of the left edge, spots were removed, and scratch and abrasion flaws were removed with Photoshop. An abrasion flaw beginning on herleft arm and extending down her dress initially looked like part of the skirt. Spots on her skirt in the vicinity of the pendant of her left arm bracelet looked like twinkling from jewelry, but there was no jewelry there so the spots were removed. Also posted to the Iberian Style in the Bustle Periods Album here.