Sisnando (or Sesnando) Davides (also Davídez, Davídiz, or Davidiz, and sometimes just David; died 25 August 1091) was a Mozarab nobleman and military leader of the Reconquista, born in Tentúgal, near Coimbra. He was a contemporary and acquaintance of El Cid, but his sphere of activity was in Iberia's southwest.
Much information can be gleaned about Sisnando's life from the detailed narratives that begin the diplomas issued by his Abbadid-influenced Mozarabic chancery at Coimbra, though the authenticity of these has lately come to be doubted.
Service with Seville and León
He was educated in Córdoba by Muslims. He was captured during a raid by Abbad II al-Mu'tadid of Seville and taken into the service of the latter. To the Arabs he was known as Shishnando. He served al-Mu'tadid as an administrator and ambassador, but he left Seville and entered the service of Ferdinand I of León in an identical capacity.
In the following years the towns of Galicia from Guimarães down to Coimbra were captured from the Moors, the latter on Sisnando's advice in 1064 or 1069, with Sisnando leading the siege and being granted the countship of the region south of the Douro from Lamego to the sea after his success. He took the title aluazir (vizier) de Coimbra.
Sisnando continued in the service of Ferdinand's successor, Alfonso VI. In March 1075 Sisnando was at Oviedo with the king—his first appearance at court—and El Cid for the opening of the Arca Santa. Later that same month he was one of many judges in a case between the bishop of Oviedo and count Vela Ovéquiz concerning the property of the monastery of San Salvador de Tol, though only he and El Cid signed the decision. Later in the year Sisnando was the principal leader of Alfonso's expedition against Seville and Granada. He took part in the expedition against Granada in 1080 as well.
Sisnando thrice (1076, 1080, and 1088) acted as an envoy from Alfonso to the taifa of Zaragoza, and on another occasion to Abdallah ibn Buluggin, the last Zirid king of Granada. To the latter Sisnando explained that the parias (tributes) that Alfonso exacted from him were intended to weaken him as a prelude to re-conquest.
Rule of Toledo
Sisnando was appointed the first governor (amil) of Toledo after its fall in 1085 and he implemented the Alfonsine policy of tolerance to the Mozarabs and Mudéjars (Muslims) of the region. His appointment was probably related to his Mozarabic roots.
Sisnando counselled Alfonso to maintain good relations with al-Qadir of Toledo by acting as the taifa's governor and protector (instead of foreign overlord interfering in its internal affairs), but when this advice was ignored the way was opened for the Almoravid conquest of Toledo, which Alfonso had treated as a tributary state; following that success the Almoravids made several gains against the Castilians. According to Ramón Menéndez Pidal, if Sisnando's far-sighted advice had been heeded, the disaster of the Almoravids and the failure of Alfonso's empire to survive his death could have been averted.
Within a short time of the conquest of Toledo Sisnando fell into disfavour with Constance of Burgundy, Alfonso's second wife, and her French court, including Bernard de Sedirac, the archbishop elect of Toledo. Ibn Bassam records that Sisnando sought to convince Alfonso to spare the mosque of Toledo, though he did not. This, however, is false, as it was not King Alfonso, but Queen Constance and the new archbishop, Bernard, who reconsecrated the mosque as a Christian church.
Within six months of the conquest of Toledo, Sisnando was back in Coimbra, but he was in Toledo for the consecration of the new cathedral in December. As Sisnandus Conimbriensis consul ("consul of Coimbra") his signature appears seventh on the document of reconsecration. He had been replaced as governor of Toledo by Pedro Ansúrez (Petrus Ansuriz).
Rule of Portugal
The primary reason for the re-creation of a county around Coimbra, separate from the northern County of Portugal, ruled by Sisnando, who had not attachments in northern Iberia, was to weaken the independence of the Portuguese magnates and expand central royal Leonese administration into newly conquered territories. Sisnando is first recorded ruling in Coimbra only on 1 May 1070, in a document that has come under suspicion. It is possible that his appointment to the countship was not made by Ferdinand in 1064 but rather was connected with his first appearance at Alfonso VI's court in 1075. In Portugal Sisnando built or rebuilt the castles of Coimbra, Lousã, Montemor-o-Velho, Penacova, and Penela. He also played some role in the foundation of a diocese in central Portugal, precisely at Coimbra.