Giraldus Cambrensis (1146-1223), also known as Gerald of Wales, was a medieval clergyman and a chronicler of this time.

He became a royal clerk and chaplain to king Henry II of England in 1184 and he was chosen to accompany one of the king's sons, John, on his first expedition to Ireland in 1185.

This was the start for his literary career and his journey to Ireland to report to king Henry II, Topographia Hibernica (Topography of Ireland), became one of his best known works

In this work Giraldus tells about a legend that belongs to Inishglora island, off the coast of Erris in County Mayo.

It is said this little island was consecrated to St. Brendan and here human corpses don't decay and, deposited in open air, they remain uncorrupted. Relatives can recognise their parents, grandfathers, great-grandfathers and all their ancestors.

He also reported another remarkable thing: mice are not found on this island and don't survive even if they are introduced to this island, as they run away immediately and plunge into the sea. If they are stopped they die instantly.