At one period he was at the Kosinitsa Monastery in Drama, Greece where he copied at least four liturgical MSS (not GNT MSS). The monastery was looted by the Bulgarians in 1917 and two of his MSS ended up in the Ivan Dujčev Centre for Slavic and Byzantine Studies. Today its library holds the richest collection of Greek MSS in Bulgaria (ca 500 codices).
The last period in Theophilos' life he spent in the Pantokrator Monastery in Constantinople where he continued to work as a scribe until his death in 1548. Apparently, Theophilos led a virtuous life; the Orthodox Church pronounced him a saint (hosios) and commemorates him on 8 July.
The oldest of Theophilos' extant MSS is Iviron cod. 342 (809) (=Greg.-Aland 1030). This manuscript contains the four Gospels, the Psalter and a work by Thomas Magistros (Thekaras). The MS is written on paper and has four illuminations. The colophon dates it to the year 7026 (= 1518). The colophon ends with this sentence: "This book was completed, with God's help, through the labours of the unfortunate, ragged Theophilos."
At another point in the MS we find his directions for use conditioned with a curse:
I beseech all who come across this book not to dare cut it up shamelessly, in order to take it apart and remove either the Gospels or the Psalter or Thekaras or any other office or part, or even a single leaf, but let it remain intact, just as it was written and bound by me. Should the binding become worn, may it be rebound just as it is now. If anyone should act against what I say, the curse of my sinful unworthy self beupon him. And may whoever owns this take care not to leave it lying idle on the shelf but always make full use of it; for this is why the book was written, so that he might not suffer the same condemnation as he who hid the talent. And if he should neglect his own salvation, let him give the book to another who cares greatly about being saved so that he might use it to gain the riches of heaven and to pray for my wretched self, who is responsible for a thousand wicked deeds and is unworthy of either heaven or earth. May the Lord have mercy upon me and deliver me from eternal damnation; therefore, I beseech you, all the holy fathers, to pray for me.