On 13 May 1917, during the first of the apparitions of Our Lady in Fatima, as the vision was vanishing, the Blessed Virgin gave the three shepherd children the following message before disappearing:
Rezem o terço todos os dias, para alcançarem a paz para o mundo e o fim da guerra!
Though the vision told the children in the third apparition on 13 July 1917 that she desired them to say the terço every day “em honra de Nossa Senhora do Rosário”, the vision also said she will introduce herself in October.

And so, on 13 October 1917, the vision introduced herself:
Sou a Senhora do Rosário.
And, then, she added:
Que continuem sempre a rezar o terço todos os dias.
We highlighted two words above: rosário and terço. In English, these two words are translated as rosary, seldom with qualifications as to the specific meanings they encode. For these words, while indeed refer to the rosary, are distinguished by degree, something which even Spanish, a Romance language close to Portuguese, does not capture. For Lusophones, the rosário is the entire Rosary, all fifteen mysteries of it; whereas the terço, as the name implies, is just one third of the rosário.
So, let us pray the terço! It is but one simple chaplet of five mysteries, but Our Lady indeed promised to obtain the end of terrible wars if we recite it each day! Perhaps, we can sing the Rosary as our grandparents did in olden times! The Holy Rosary will secure peace for the world more surely than all beauty pageants combined could ever do.