Saint Barnabas was born in Cyprus. He was one of the early converts in Jerusalem and vouched for St Paul when he appeared before the elders there. He accompanied Paul on his first missionary journey and later went to Cyprus with his cousin John Mark (Mark the evangelist) to preach the gospel there. He was probably martyred at Salamis in Cyprus, some time before the year 61. See the articles in the Catholic Encyclopaedia and Wikipedia.

Chromatius was Bishop of Aquileia, at the head of the Adriatic Sea, and died about 406-407. He was probably born at Aquileia, and in any case grew up there. He was one of the most celebrated prelates of his time and was in active correspondence with his illustrious contemporaries, St Ambrose, St Jerome, and Rufinus. Himself a scholarly theologian, he urged these three friends to the composition of many learned works. His own surviving works include a set of treatises on St Matthew’s Gospel and a homily on the Beatitudes.

Red is the colour of fire and of blood. Liturgically, it is used to celebrate the fire of the Holy Spirit (for instance, at Pentecost) and the blood of the martyrs.