RCSI Heritage Collections houses a medieval medical manuscript of unique research interest. Ten years ago, our then special collections librarian wrote a blog post on the ‘Lentaigne Manuscript’ (RCSI/MS/97), telling of the history of the 1851 donation to RCSI Library and its Lentaigne namesake, and referencing previous research published in 1943, by the late RCSI Professor J.D.H. Widdess ( PRACTICA MAGISTRI JOHANNIS ARDERNE. (An Account of an early 15th Century Manuscript in the Library of the Royal College of Surgeons in Ireland .) Recently, a new piece of research on RCSI/MS/97 has been published by Peter Murray Jones , Fellow, King's College, Cambridge, giving us more to know and love about RCSI’s own ‘Arderne Manuscript’. RCSI/MS/97 - marginalia and illustrations appear throughout the manuscript Master surgeon John Arderne (1307–c.1380) had served King Edward III as an army surgeon at the battle of Crécy in 1346. In 1376, Arderne wrote PRACTICA MAGISTRI JOHANNIS ARDERNE, whic