Today's first reading gives us our one and only Scriptural look at Lydia, the dye merchant of Philippi who was one of Paul's very first European converts. It's an interesting story.
Paul's typical missionary practice was to begin proclaiming "Christ and him crucified" in the synagogue. We have a sample of what may have been his typical introductory sermon in Acts 13: he goes through the history of Israel (including a plug for King Saul, his namesake) to lead into the Good News that all of those promises and hopes have been fulfilled, and more, in Jesus. Arriving in Philippi, which was where old Roman soldiers spent their golden years, Paul evidently did not find a synagogue, because on the Sabbath day, he went in search of a place of prayer, and found it on the banks of a river in the person of a group of women. Lydia was among those who "listened to Paul's words."
Lydia is described as a "God-fearer" (a Gentile who was intellectually converted to the religion of the Jews); she is seen at prayer on the Sabbath, another indication of her interior connection with Judaism. So she is a kind of bridge-figure for Paul's first venture to the western reaches of the Mediterranean world. Presumably she was the head of her household, because Luke (part of the "we" of the story) says that "she and her household were baptized."
Lydia is almost an image of the community that became the Church of Philippi, Paul's favorite community. Some really imaginative types even like to speculate that Paul married Lydia (!), thought that is really hard to square with his express desire that the Corinthians follow his example of singleness for the Lord (1Cor 7). I think that also diminishes Lydia's status; as if she had to be bound to the apostle to count. Why not see her, instead, as a lay woman who understood what it meant to help the Gospel penetrate society from within, and who did just that, from her stance as a successful and influential woman in the world of business?