The patron of Morwenstow in Cornwall, Saint Morwenna lived in the sixth century and came from an Irish-Welsh family. She is believed to have been trained in Ireland before crossing over to Cornwall where she made her home in a little hermitage at Hennacliff, (the Raven's Crag) which was later called Morwenstow (Morwenna's holy place). It stands on top of a high cliff overlooking the Atlantic Ocean.

According to legend, when the villagers were building a new church, she collected a stone from under a cliff on the beach and carried it on her head to the place where she wanted the church built. The villagers wanted to locate the church elsewhere. St Morwenna rested on the way and lay the stone down on the ground - whereupon a spring of water appeared. She got her church and a well was built over the spring.

Early in the 6th century, while she lay dying, her brother, St Nectan, came to see her, and she asked him to raise her up so that she might look once more on her native shore. She was buried at the church in Morwenstow.

A painting was later found on the north wall of the Morwenstow church, thought to represent St Morwenna. It shows a gaunt female clasping a scroll to her breast with her left hand; the right arm is raised in blessing over a kneeling monk.

Morwenna is depicted in a stained glass window of the parish church, St Morwenna and St John the Baptist's.