John Macías, OP (or Massias, born Juan de Arcas y Sánchez; 2 March 1585 – September 16, 1645), was a Spanish-born Dominican friar who evangelized in Peru in 1620.

His image is located at the main altar of the Basilica of Our Lady of the Rosary of Lima and is venerated by the local laity in Peru.

It is said that as he began to seek God's will for his life; he was frequently visited by the Blessed Virgin Mary and by his patron, St. John the Evangelist.

[2] At the age of 25, Macias then started working with a wealthy businessman who offered him an opportunity to travel to South America.

The ships which crossed the seas in those days carried all sorts of people: soldiers led by the lure of gold or glory; missionaries going to preach the Gospel; merchants and those seeking adventure; and also the poverty stricken hoping to find better luck.

Macias was a contemporary of St. Martin de Porres who was in the Priory of Santo Domingo, (otherwise known as Holy Rosary).

[6] Macias, however, expressed a greater desire to spend more time in contemplative solitude rather than engage in conversational activities with others.

But his official position as the priory's porter, which he held for over 20 years and went against his natural inclinations of solitude, served to continue disciplining his vow of obedience.

Macias' image, along with that of the more famous saint, Martin de Porres, (his friend and fellow Dominican laybrother) are paraded around the streets and venerated by the faithful of Peru.