This is the letterhead of His All Holiness the Oecumenical Patriarch, and I recognise his signature in the margin (I have received letters from him myself).
The beginning of the top Caligraphy is his name, you can make out the letters: "+ Β α ρ θ ο λ ο μ α ι ο ς " ("+Bartholomaios").
α o λ α ι ο
+ Β ρ ο
The base of the Cross is the base of the Β
The α is at the top of the Β
The tail of the α joins the curve of the ρ
The tail of the ρ joins the θ below it .....etc
I've never been able to work out the rest of it, but it contains the word "Κωνσταντινουπόλεως" ("Of Constantinople") so I assume its his full title:
+ Βαρθολομαίος Αρχιεπίσκοπος Κωνσταντινουπόλεως, Νέας Ρώμης και Οικουμενικός Πατριάρχης
+ Bartholomew, Archbishop of Constantinople, New Rome and Oecumenical Patriarch