Every line above is reproduced from the holding institution’s own catalogue entry, which is linked. Where their title, date or attribution differs from ours, theirs is the one printed here.
His name is disputed. The door is not. The Flemish Art Collection's record has the saint stopping a crowned emperor at the church door, reproaching his cruelty and forcing him to confess.
The picture is named for its background. White-clad monks on the hillside, and a similar tale in his legend, got it retitled for Romuald. The man at the door wears a jewelled bishop's mitre, which Anne Leader argues rules Romuald out: never a bishop, always shown in a hermit's white robes.
First catalogued as Ambrose refusing Theodosius: the museum changed its mind, the mitre did not.
Sources: Vlaamse Kunstcollectie / KMSKA object record · Anne Leader, "The Church and Desert Fathers in Early Renaissance Florence: Further Thoughts on a New Thebaid" · OKV / Vlaamse overheid, "Van Fra Angelico tot Tintoretto" · Studies in Church History (Cambridge University Press), "Otto III's Penance" · Vlaamse Kunstcollectie, Flemish Primitives database, 'Saint Ambrose refuses Emperor Theodosius Admission to the Church', KMSKA inv. 3.
Printed on demand. Public-domain masterwork, reproduced from a 8,633 px master of the original. The whole image is printed — never cropped to fit the sheet — so every sheet carries an archival margin, and the dimensions and resolution listed above are the ones you receive.