it seemed good to me also, having traced the course of all things accurately from the first, to write to you in order, most excellent Theophilus;
Most excellent Theophilus --     It is probable that during Paul’s two year imprisonment at Caesarea that Luke had all this time and opportunity to meet and interview the eye-witnesses of whom he speaks. For instance, in Acts 21:16 we met Mnason who undoubtedly was one of the earliest Christian. (Some translate the description of him to mean "An original disciple" "a charter member".) Paul lodged with him in Jerusalem, and Luke was with this party. We know, for example, that he met Philip (Acts 21:8), who was undoubtedly one of Luke’s sources.