On March 25th, 1646, King John IV declared that the Blessed Virgin Mary, the Immaculate Conception, would henceforth be the Queen and Patroness of the Kingdom of Portugal, offering to her the royal crown, which would never again be worn by a Portuguese monarch. 
The same King also decreed, that the students at the University of Coimbra -Portugal's most prestigious university- before receiving their degree, would henceforth swear an oath to defend the Immaculate Conception of the Mother of God.
Here is the text of the 1646 Royal decree of King John IV of Portugal declaring the Blessed Virgin Mary, the Immaculate Conception, the Queen and Patroness of Portugal, which was later confirmed by Pope Clement X in the papal bull, Eximia dilectissimi.
