Thanks to his deep knowledge of Islamic and Christian traditions, Sesnando became instrumental in the reconquest of Coimbra in 1064, a crucial event in the expansion of Christian territory. The conquest consolidated Coimbra as a strategic stronghold and laid the foundations for the future County of Portucalense, which would later give rise to the Kingdom of Portugal.

During his reign, Sesnando proved to be a brilliant administrator, promoting the reconstruction and development of Coimbra. He was responsible for the creation of infrastructures that revitalized the city and fostered coexistence between different religious communities. This period of growth marked the beginning of Coimbra's rise as a political, economic and cultural center, reinforcing its importance in the medieval context. Sesnando's strategic vision and leadership skills left a lasting impact on the history of Portugal.

D. Sesnando is buried in Old Cathedral of Coimbra, one of the city’s most emblematic monuments. This cathedral, built in the 12th century, reflects the splendour of the Romanesque style and is a testament to Coimbra’s importance as one of the main centres of Christianity in the Iberian Peninsula. The Sé Velha stands out for its architectural grandeur, with its towers, merlons and iconic portal decorated with sculpted motifs that symbolise the transition between the medieval and Renaissance worlds. The site is a must-see for anyone wishing to delve into the history of Coimbra and the legacy of figures such as Sesnando, who helped define the city as a landmark in the Reconquista and the formation of Portugal.