As was the case in much of Andalucía, the Reconquista destroyed Baeza's mosque and in its place built a cathedral. It's a stylistic melange, though the predominant style is 16th-century Renaissance, visible in the facade on Plaza de Santa María and in the basic design of the three-nave interior (by Andrés de Vandelvira).
You can climb the tower for great views over the town and countryside. The tower's base dates from the 11th century and was part of the minaret of the mosque. The cathedral's next oldest feature is the 13th-century Gothic-Mudéjar Puerta de la Luna (Moon Doorway) at its western end – now the visitor entrance – which is topped by a 14th-century rose window. Inside, there's a clear transition from the nave's two easternmost bays, which are Gothic, with sinuous ceiling tracery, pointed arches and gargoyled capitals, to the Renaissance-style bays further west with their Corinthian capitals and classical square and circle designs. Audio guides in several languages are available for €1.
The broad Plaza de Santa María was designed to be a focus of Baeza's religious and civic life. On its north side you can look into the main patio of the 17th-century Seminario de San Felipe Neri, a former seminary, which now houses part of the Universidad Internacional de Andalucía, teaching postgraduate courses.