Looking at: "... fue la capital del Califato … que fue proclamado por Abderramán III en 929" > My first thoughts were that AbdulRahman III had perhaps proclaimed Córdoba as his capital in 929 AD, which would have required "proclamada" to agree with the feminine noun "capital". Then I remembered that he had actually declared himself [very controversially !] to be "the Caliph of all Muslims, everywhere" (including those in Baghdad, and Syria, and even those in the Fatimid Empire in North Africa !) - so "proclamado" presumably agrees with "Califato"?
As I'm sure Inma knows, Seville was the first capital of Al-Ándalus [was it?], and Abdul-Rahman the First transferred his seat of power to Córdoba in 766 AD.