The logo was approved by King Charles I of Spain in 1551. By the late 1570s and after a papal bull of Pope Pius V, the seal was modified, replacing the icon of "Virgen del Rosario" with Saint Mark. It is uncertain which colors were used on this seal, because documents in the 16th century were only black-and-white paper prints. It was not until 1929 when the colors—blue for the ocean, black or brown for the saint's icon, a light blue background, and silver for columns—became popular.