Recent research by local historians seems to confirm what oral tradition has passed down to us: originally, the ancient medieval church of St. Nicholas, existing at least since 1308, was a Greek Orthodox rite church. After its acquisition by the Diocese of Agrigento in 1333, it was converted to the Latin rite. The small medieval church of the castle and hamlet of Delia, located at the entrance of the settlement on the old road linking Delia to Naro, may have changed its dedication around the mid-17th century to Mary Most Holy of Grace, as suggested by the name of the district cited in a 1651 document.
The first certain mention of the church dates to 1667, when the bishop visited Delia. We know that the temple contained only one altar, the main one, dedicated to Our Lady of Grace. In 1693, Marchesa Giulia Lucchese established in it a legacy of 14 annual oncie, probably connected to the earthquake of Val di Noto, which spared Delia thanks to the intercession of Our Lady of Grace.