Osanna
northumbrian princess and saint
Feast: 18 July (not on the universal Roman calendar; kept in the Roman Martyrology or local calendars)
Who they were
Osana was a Northumbrian princess, whose local following as a saint developed informally after her death, though she was never officially canonised. Centuries after her death, she was described by the Norman-Welsh chronicler Giraldus Cambrensis (died 1223) as the sister of King Osred I of Northumbria, which would make her the daughter of King Aldfrith of Northumbria. Osana was depicted by Giraldus as inflicting a miraculous flagellation from her grave in Howden, Yorkshire, upon a concubine of the priest of the collegiate church there, a moral tale intended to inculcate clerical celibacy.
Summary from Wikipedia (CC BY-SA 4.0), until this page is written up in full.
The miracles
Limited information available on this saint.
Why that counted as sanctity
Limited information available on this saint.