Theophylact of Ohrid
Catena Aurea · Lukasevangelium 1
Forasmuch as many have taken in hand to set forth in order a declaration of those things which are most surely believed among us, Even as they delivered them unto us, which from the beginning were eyewitnesses, and ministers of the word: It seemed good to me also, having had perfect understanding of all things from the very first, to write unto thee in order, most excellent Theophilus, That thou mightest know the certainty of those things, wherein thou hast been instructed.
(in loc.) He writes to Theophilus, a man probably of some distinction, and a governor; for the form, Most excellent, was not used except to rulers and governors. As for example, Paul says to Festus, Most excellent Festus. (Acts 26:25.)