ONDON - Richard Leigh, a writer of alternative history who unsuccessfully sued for plagiarism over themes in Dan Brown's blockbuster novel "The Da Vinci Code," has died, his agent said Friday. He was 64. U.S.-born Leigh, who had lived in Britain for three decades, died in London on Nov. 21 of causes related to a heart condition, the Jonathan Clowes Agency said. Leigh was co-author of "The Holy Blood and The Holy Grail," a work of speculative nonfiction that claimed Jesus Christ fathered a child with Mary Magdalene and that the bloodline continues to this day. A best-seller on its...