He claimed that Islam was only a branch of Christianity in his book Alcorani seu legis Mahometi et evangelistarum concordiae liber ( 1543 ) .
Only a branch of Christianity is a simple heresy that could be reintegrated into Christianity .
He claimed that Islam was only a branch of Christianity , a simple heresy that could be reintegrated into Christianity , in his book Alcorani seu legis Mahometi et evangelistarum concordiae liber ( 1543 ) .