Why was Saint Stephen the first martyr?

A:The martyrdom of Stephen is in Acts of the Apostles at chapter 7, taking place soon after he was appointed a deacon in the church at Jerusalem and before the authorities began to take note of the apostles and the other deacons, on account of the wonders and miracles attributed to him. In commenting on whether this really happened, Raymond E. Brown (An Introduction to the New Testament) says that we can never verify the martyrdom or even existence of Stephen.

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If the existence and martyrdom of Stephen are open to reasonable doubt, as Brown and others state, the story of Stephen could have been written as an introduction to Saul as the callow youth who supported stoning of Stephen but was unwilling to participate like a man. This provides a graphic contrast to the saintly man he was to become.