In 2004, Dick Henry, a professor of astronomy at Johns Hopkins University, proposed the adoption of a calendar which he credits to Robert McClennon. In this way, C&T is the direct predecessor of the Hanke-Henry Permanent Calendar. Henry argues that his proposal will succeed where others have failed because it keeps the weekly cycle perfectly intact and therefore respects the Fourth Commandment, which requires worship every seven days[1]. However, other calendar proposals that intercalate entire weeks do exist, such as the Symmetry454 and New Earth calendars.