António Bernardo da Costa Cabral (Algodres, 9 May 1803 - Oporto, 1 September 1889), 1st earl and 1st marquis of Tomar, and more simply known as Costa Cabral, was a Portuguese politician. Among other positions, he was a member of parliament, a peer of the realm, acting advisor to the state, minister for Justice and Ecclesiastical Affairs and minister of the Realm. His influence on Portuguese politics during the first period of the constitutional monarchy was such that it can be said that the entire policy for the institutional consolidation of liberalism which characterised the reign of Queen Maria II revolved around him. In 1841, he also became the Grand Master of the Masons.
António Bernardo da Costa Cabral was still at the beginning of his political career, as a mere member of parliament, when he acquired parts of the Convent of Christ and its enclosure in 1838. He had decided to make it his summer residence and to turn the Mata dos Sete Montes area into farmland. The land he purchased was concentrated around the Claustro dos Corvos, though several other pieces of land spread around the monument also came into his ownership. Testimony of his love for these magical places and a clear understanding of their supreme value can be seen in the urgent measures he took to safeguard the convent, which had been plundered ever since the brothers of the Order of Christ had left. When he became a government minister in 1839, he ensured guards were installed to protect Portugal's most important monument, paid for urgent repairs out of his own pocket, particularly on the Charola, and put a stop to the removal, under disastrous conditions, of the remaining valuable artefacts to Lisbon. When he was cast into the political wilderness, it was to Tomar that Costa Cabral retired, where he wrote a history of the city that focused on the central theme of the Convent. At the age of 86, after returning from his long sojourn in the Vatican, he passed the Convent on to his eldest son and retired to Foz do Douro to live out his remaining years. For three generations, up until 1942, the Convent remained under the care of his descendants, who protected, maintained and cherished it.