APOCRISIARIUS, a Latinized title (originally equivalent to Agens in rebus ?) from the Greek (meaning 'he who answers', i.e. for his sender), rendered in purist Latin as responsalis, is a high diplomatic representative, in modern terms ranking as ambassador, in two spheres

Ecclesiastic

• The representative of a
  • The most important Apocrisiarii were exchanged between Rome (the Pope, head of the Catholic church) and 'the second Rome' Constantinople, the capital of Byzantium (the continuation of the eastern Roman Empire; orthodox after the Great Schisma - the patriarch of Constantinople was in many respects a major minister of the Greek Emperor).

The papal post has been filled by several first rate clergymen, some of which even went on to become pope themselves (St. Gregory I the Great, Sabinianus, Boniface III, Martin I)

Secular

• Venice

Sources and References

[various articles in the Catholic Encyclopaedia]