The Historia Divae Monacellae is the medieval Latin hagiography of Melangell (Latin: Monacella), an early medieval Welsh saint whose cult is centered at St Melangell's Church, Pennant Melangell. The Historia chronicles the legendary life of Melangell, a consecrated virgin and hermit in the forest of Powys, and her encounter with a prince who grants her land as a sanctuary after she supernaturally protected a hare from his hunting dogs. She later established female monastics in the area.
The Historia's authorship is subject to debate, but it was probably composed at some point in the late Middle Ages in or near Pennant Melangell, and was based on previous literature and local folklore. Several manuscripts survive, three of which are complete. The Historia was first printed in 1848. Various interpretations of the Historia have been put forth, such as it being written to defend Pennant Melangell's sanctuary rights in a time when Welsh churches were being threatened by local rulers. Others have analysed the Historia as a cautionary tale for men seeking to harm virgins, or as representing the anchoritic tradition.