Human settlement of the island dates from circa 3000 BC and it are remains of several Neolithic burial chambers known as ' heel @-@ shaped cairns ' . Little is known of the pre @-@ Celtic and Celtic eras , but when the Norse arrived it is likely they found a religious settlement as the name of the island derives from Papey Stóra meaning " Big island of the Papar " ( Celtic monks ) , in distinction to Papa Little some 12 kilometres ( 7 @.@ 5 mi ) to the west .