This has very little to do with harmony with Christians, she was Jewish.
Mary or Maryam, mother of Jesus, is the only woman named in the Qur’an. She is named 70 times and the Koran call hers the greatest of all women. A chapter in the Qur’an is titled “Maryam”.
There is a cult of Maryam, very devoted Islamists.
Well!
It's no WONDER then that Francis appears to get along so well with them!
It would all be peace and flowers now if that Hammer; Charles Martel; hadn't gotten so nasty with them way back when.