Modern scholarship inclines to the view that "L'incoronazione" was the result of collaboration between Monteverdi and others, with the old composer playing a guiding role. Composers who may have assisted include Sacrati, Benedetto Ferrari and Francesco Cavalli. Ringer suggests that Monteverdi's age and health may have prevented him from completing the opera without help from younger colleagues; he speculates about an arrangement resembling "the workshop of Rubens, who might design a painting and handle the important details himself but leave the more mundane aspects ... to younger apprentice artists." The musicologist Alan Curtis believes that only a single collaborator was involved, and published his 1989 edition of "L'incoronazione" under the joint authorship of Monteverdi and Sacrati. The American musical analyst Eric Chafe's study of Monteverdi's tonal language supports the collaboration theory and postulates that some of the sections in question, including the prologue, the coronation scene and the final duet, reflect Monteverdi's intentions and may have been written under his direct supervision.