Rodrigo (died 873) was the first count of Castile, governing from about 862 to his death. Some Iberian Muslim writers refer to a brother or brother-in-law of Ordoño I, while others assign the same role to a Ruderick without stating a relationship, and the references have been interpreted as referring to the same man. This has been used by authors such as Fernández de Béthencourt, writing in 1897, to suggest that count Rodrigo was a son of Ramiro I of Asturias and his supposed second wife, 'Urraca Paterna' (actually just Paterna, Urraca being the wife of a later prince Ramiro) and half-brother of Ordoño, but Barrau-Dihago dismissed this interpretation for want of evidence.
Also, it would be highly unlikely that Rodrigo was the son of Ramiro and Paterna who did not marry until around 842 and would be repopulating Amaya in 860, although due to the missions entrusted to him, it is probable that he was close to the royal house.
He was created governor of the eastern march (marca oriental) of the realm, the territory called Al-Qila by the Arabs, which later became the county of Castile, by Ordoño, possibly upon the latter's assumption of the crown. He took part in Ordoño's Repoblación, repopulating Amaya in 860. Amaya was known as the "patrician city" because at one time it had been the capital of eight of the provinces of the Visigothic Kingdom of Toledo which had been conquered in 711-712 by Tariq ibn Ziyad: In era DCCCLCLVIII populavit Rudericus comes Amaya et fregit Talamanca and built a wall with towers around the city. He was at the side of the king in many battles of the Reconquista, including the siege and sack of Albelda in 859.
In 863, the 'brother of Ordoño' fought Muslim troops, and in 865 Rodrigo was defeated magnificently at Bureba by the troops of the emir of Córdoba, resulting in the sacking of his castles and those of other noblemen in Castile, which brought to a temporary halt the process of reconquest and repopulation of the area. Upon King Ordoño's death in May 866, he was succeeded by his son Alfonso III of Asturias who at that time was about 18 years old. Alfonso was overthrown and took refuge in Castile. Count Rodrigo entered the Kingdom of Asturias with his troops to support the young monarch, and remained at his side for some time.