The Alvito region has been inhabited since the Neolithic, and during the period of Roman domination several villae were established nearby, later occupied by Visigoths and Moors. During the Reconquista, Alvito was conquered by the Portuguese in 1234, being later (1251) donated by King Afonso III to Estêvão Anes, chancellor of the kingdom, who promoted the settlement of the area.
The village gained a foral (letter of feudal rights) in 1280, confirmed by King Dinis I in 1283. In 1296 an annual fair was established, attesting the rapid development of the region. In 1387, King John I donated Alvito to knight Diogo Lobo in exchange for his services in the decisive Battle of Aljubarrota (1385), and in 1475 the title of Baron was granted to the rulers of Alvito.
The 15th and 16th centuries were a time of strong economic and populational development of Alvito, which reached 1700 inhabitants in 1527. The Castle of Alvito was rebuilt between 1494 and 1504, and its architecture and decoration show an interesting mix of Manueline (Portuguese late Gothic) and Mudéjar (Arab-influenced) styles, typical of the Alentejo region. Also the main church (matriz) of Alvito, in a mix of Manueline and early Renaissance styles, dates from the early 16th century.
This church was built in the end of the 15th century, combining several styles, from Gothic to Baroque, from Manueline to Renaissance and Mannerism. It has an interesting Renaissance portal and big buttresses with conic tower endings and battlements on top. In the south wing rises the clock tower with its marble sun clock. 17th century tiles, mainly yellow over a white background, predominantly cover the interior. The main chapel dates back to the 15th century, preceded by an arch framed by pilasters made of typical Alentejo stone. Thirty coffers divided in six rows split the cradle vault.