sentences:  The double monastery of Hartlepool Abbey, a walled enclosure of simple wooden huts surrounding a church had been founded in 640 by Hieu, an Irish recluse in Northumbria.In 649, Aidan sent Hieu to establish a monastery at Healaugh near Tadcaster, and named Hild abbess at Hartlepool.Around 657, Aidan asked her to found an monastery at Streoneshalh.