Joachim was, according to Christianity, the husband of Saint Anne, the father of Mary, mother of Jesus, and the maternal grandfather of Jesus.
Saints Joachim and Anne, Parents of the Virgin Mary
12th-century German Nativity of Mary, with Joachim wearing a Jewish hat
Saint Joachim
According to apocrypha, as well as Christian and Islamic tradition, Saint Anne was the mother of Mary, the wife of Joachim and the maternal grandmother of Jesus. Mary's mother is not named in the Bible's canonical gospels. In writing, Anne's name and that of her husband Joachim come only from New Testament apocrypha, of which the Gospel of James seems to be the earliest that mentions them.
The mother of Mary is mentioned but not named in the Quran.
Greek icon of Saint Anne with the Virgin, by Angelos Akotantos
Saint Anne with Mary as a child
Birth of St. Anne, by Adriaen van Overbeke (c. 1521–1525)
Feast of Saint Anne in Marsaskala Parish Church [fr], Marsaskala, Malta