The 85-year-old announced the decision in Latin during a meeting of Vatican cardinals this morning.
He said that because of his age and diminishing strength, he didn't feel he could carry on.
On the Island, Lord Bishop Robert Paterson has described the Pope as having a formidable intellect but also formidably conservative.
He admits the resignation has come as a surprise:
Island's first rapid EV charger being installed
Once operational, the site will retain its existing charger, increasing overall capacity to four charging bays
Mooir Vannin could be first of many
Dr Alex Allinson, who is retiring as Ramsey MHK at this year's general election, gave evidence to the final hearing by the independent panel.
'Significant investment or redevelopment' needed at Ramsey District Cottage Hospital
Manx Care is 'planning a sustainable long-term solution'
Braddan Commissioners open expressions of interest for TT camping at Roundhouse
Local authority wants to provide family friendly accommodation