I mentioned last week that Surah Maryam is loaded with the work of being ambassador to the Christians. The precedence for this was set down in Islamic traditional history. One of the first encounters that Muhammad’s followers had with a Christian community was when a number of Meccan Muslims sought sanctuary from Qurayshi persecution in the Kingdom of Axum (Ethiopa). The story, as told a hundred years after the fact by Ibn Ishaq, is that the Quraysh sent emissaries who tried bribing the king of Axum to extradite the refugees back to Mecca. The king brought the Muslims in for evaluation, whereupon they presented some of Surah Maryam to him, and he declared their message truth and sent the polytheists back to Mecca.
We don’t have any historical confirmation of this story, knowing very little about the king at that time except that he minted coins, which we may or may not have extant copies of.
The Quran itself makes no allusion to the first emigration or any intended purpose for the surah besides redacting the perceived errors of Christians and rebuking them. It starts with Zechariah, Mary, and Jesus, but then goes back to list the other patriarchs in order to open its rebuke to wider audiences.