The Blessed Virgin Mother under the invocation of the Immaculate Conception (venerated in the Ducal Chapel of the Palace of Vila Viçosa) had earlier been acclaimed "Queen" and Patroness of the kingdom by King John IV on March 25, 1646[5] following a referendum of the Empire that lasted 6 years and asked subjects: 1.
Later, in 1818, a royal decree stated that the Order would be given as a military award in four (4) classes of Grand Cross, Commander, Knight, and Servant.
Just after the Second World War, it was bestowed on Prime Minister António de Oliveira Salazar by Queen Amelia when she visited Portugal for the last time.
He has since then distinguished many Portuguese personalities (including giving the Order's Medal of Merit to among them football star Cristiano Ronaldo).
The Order is divided in four grades: The order's insignia was designed by the French painter Jean-Baptiste Debret (1768–1848), who was in charge of creating in Rio de Janeiro an arts and crafts lyceum (Escola Real de Artes e Ofícios) under the auspices of King João VI and the Marquis of Marialva.