He was a major figure of the second half of the seventeenth century, serving as Royal Chaplain and Councillor of State of Portugal, later being created a Cardinal by Pope Innocent XII in 1697.

[5] In Lisbon, Luís de Sousa was admitted in the household of Prince Teodósio, the heir-apparent son of the new Portuguese king John IV, starting his religious studies in the Jesuits College of Santo Antão.

[6] On 8 February 1651 went to Rome, to the Pontifical Gregorian University, where he obtained a doctorate in canon law [7] after what he spend some years working in the Roman Curia.

When of his return to Portugal, Luís de Sousa spent some months in Venice, Flanders, Netherlands and France, arriving to Porto on 26 September 1656.

[10] In the same year, 1669, the Regent appointed Luís de Sousa as Grande Almoner, Royal Chaplain and Canon of the Lisbon Cathedral chapter.