All three authors anchor the histories of their respective peoples by dating the births of the founders (Romulus, Moses, and Jesus) and narrate the stories of the founders' births from God, so that they are sons of God. Each founder taught authoritatively, appeared to witnesses after death, and ascended to heaven. Crucial aspects of the teaching of all three concerned the relationship between rich and poor and the question of whether "foreigners" were to be received into the people. Mark, written around 70 AD, provided the narrative outline for Luke, but Mark contains comparatively little of Jesus' teachings, and for these Luke likely turned to a collection of sayings called Q, which would have consisted mostly, although not exclusively, of "sayings". Mark and Q account for about 64% of Luke; the remaining material, known as the L source, is of unknown origin and date. Most Q and L-source material is grouped in two clusters, Luke 6:17–8:3 and 9:51–18:14, and L-source material forms the first two sections of the gospel (the preface and infancy and childhood narratives). Luke was written to be read aloud to a group of Jesus-followers gathered in a house to share the Lord's supper. The author assumes an educated Greek-speaking audience, but directs his attention to specifically Christian concerns rather than to the Greco-Roman world at large. He begins his gospel with a preface addressed to "Theophilus" (; "cf." ): the name means "Lover of God," and could mean any Christian though most interpreters consider it a reference to a Christian convert and Luke's literary patron. Here he informs Theophilus of his intention, which is to lead his reader to certainty through an orderly account "of the events that have been fulfilled among us." He did not, however, intend to provide Theophilus with a historical justification of the Christian faith – "did it happen?" – but to encourage faith – "what happened, and what does it all mean?" Following the author's preface addressed to his patron and the two birth narratives (John the Baptist and Jesus), the gospel opens in Galilee and moves gradually to its climax in Jerusalem:  The structure of Acts parallels the structure of the gospel, demonstrating the universality of the divine plan and the shift of authority from Jerusalem to Rome:  "The gospel – the acts of Jesus":  "The acts of the apostles"  Luke's theology is expressed primarily through his overarching plot, the way scenes, themes and characters combine to construct his specific worldview.