Falls the Shadow

Soft stuff, with a certain breathiness, about the Holy Crown of Saint Stephen stolen from the Vatican which British agent Charles Forsyth is supposed to secure accompanied but not really assisted by Nicola Beaufort supposedly in love with Tony Rothman, another agent or perhaps doubling as one? This finds them for the most part in Romania and it's strung out with intercontinental touches which somehow still survive behind that lace iron curtain.