Vatican officials have mounted an extraordinary challenge to the ancient Order of Malta. But what is the row really about?The Sovereign Military Order of Malta is one of the more improbable success stories of the 21st-century Church. Founded in 1099 to provide hospital care and military defence in the Holy Land, it has retained much of its medieval tradition and ceremony. But it has also, by gradual reform, become a powerhouse of international aid. More than 100,000 members, medical staff and volunteers are offering practically every form of charitable assistance around the world, from handing out sandwiches to the homeless...