This is a history book. Cardinal Mai has left recorded his judgment that, 'in matter of fact, the whole administration of the Church is learnt in the letters of the Popes'. I draw from this judgment the inference that of all sources for the truths of history none are so precious, instructive, and authoritative as these authentic letters contemporaneous with the persons to whom they are addressed. The first which has been preserved to us is that of Pope St. Clement, the contemporary of St. Peter and St. Paul. It is directed to the Church of Corinth for the purpose of extinguishing a schism which had there broken out. In issuing his decision the Pope appeals to the Three Divine Persons to bear witness that the things which he has written 'are written by us through the Holy Spirit, ' and claims obedience to them from those to whom he sends them as words 'spoken by God through us'.