Alfonso de la Cueva-Benavides y Mendoza-Carrillo, marqués de Bedmar (first name also spelled Alonso, often used was the title Bedmar) (1574 – 10 August 1655) was a Spanish diplomat, bishop and Roman Catholic cardinal. He was born in Bedmar, in what is now the province of Jaén. Alfonso was the son of Luis de la Cueva-Benavides, 2nd señor of Bedmar, and Elvira Carrillo de Mendoza y Cárdenas.
Alfonso was born at Bedmar, now Bedmar y Garciez, province of Jaen, Spain. At an early age, he pursued a military career at the side of his father, who was the captain general of the Canary Islands. After 1590, he took his father's place in his absence, and a year later was named captain of the Harquebusiers. After the death of his father in 1599, he became the 3rd lord of his house and became a commander of a Cavalry company.
On 23 December 1606King Philip III of Spain made him the Spanish ambassador to the Republic of Venice. This was an important position due to the amount of information concerning European affairs which passed through the hands of the Spanish representative. On 16 April 1610 King Philip III awarded him the title of Knight of the Order of Alcántara. In 1614, aged around 42, he was made Marqués de Bedmar, which he would resign when promoted to the cardinalate.
In 1618 king Philip III charged him with the devolution of the territories conquered by the Spanish forces in Piedmont to the duke of Savoy. In 1616 Venice concluded an alliance with France, Switzerland, and the Netherlands to counter Spain's power. Bedmar was instructed to destroy this league and, with Pedro Téllez-Girón, 3rd Duke of Osuna, viceroy of Naples (1574–1624), and the Spanish Governor of the Duchy of Milan, Gómez Suárez de Figueroa, 3rd Duke of Feria, planned a naval invasion to bring the city closer to the Spanish sphere of influence. The scheme was to be carried out on Ascension Day in 1618 but was revealed by the French, and Bedmar, protected by his position from arrest, left Venice.