Pope St. Gregory I (the Great) was a prolific writer of letters. When he sent Augustine off the convert the heathen Saxons to Christianity, he asked for favors from and gave advice to many of the other worthies of his day.  I have provided the translations into English and taken liberties in summarizing his correspondence regarding Augustine's mission, tongue-in-cheek.

Pope Gregory I's Letters About Augustine's Mission to England

EPISTLE XXVIII: To  Augustine, Bishop of the Angli(5).

Congrats on converting the English, but don't get too big for your britches. 

EPISTLE XXIX: To Bertha, Queen of the Angli(6).

Congrats on helping Augustine convert the English and your husband.

EPISTLE LIV: To Desiderius, Bishop of Gaul(6).

Lay off the pagan literature, and please assist Augustine on his way to England

EPISTLE LV: To Virgilius, Bishop Of Arelate (Arles)(7).

Keep up the Good Work, however, your friends & neighbors are misbehaving & you should get involved. Please assist Augustine on his way to England

EPISTLE LVI: To Aetherius, Bishop of Lugdunum (Lyons.)

Keep those cards and letters coming, and perhaps you should hold a synod.  Tell Augustine to get a move on.

EPISTLE LVII: To Aregius, Bishop of Vapincum(9).

Hope you're feeling better, and root out those heretics. Make sure these monks I'm sending get to Augustine.

EPISTLE LVIII: To Divers Bishops of Gaul,

I'm counting on you guys to make sure these monks I'm sending to Augustine get there, and soon.

EPISTLE LIX: To Theoderic, King of the Franks(2).

EPISTLE LX: To Theodebert, King of the Franks(3).

EPISTLE LXI: TO Clotaire, King of the Franks[4].

EPISTLE LXII: TO Brunichild, Queen of the Franks[5].

Oh great monarchs, please hold a synod and knock off selling church appointments.  Thanks for putting up Augustine, I'm sending Laurencius & Mellitus to England, too.

EPISTLE LXIV: To  Augustine, Bishop of the Angli[6].

I know I told you this stuff before, here it is again.  How to divvy up the collection plate, marriage, incest, politics, how long after sex one can go to church, and wet dreams are all covered.

EPISTLE LXV: TO Augustine, Bishop of the Angli [4].

You're the man over there in England. York, London, and those British bishops all report to you now.

EPISTLE LXVI. TO Edilbert, King of the Angli.