In April 1900, Professor L. A. Grosclaude of Geneva proposed the Invariable Calendar, New Era Calendar, or Normal Calendar with 12 months and four 91-day quarters of exactly 13 weeks.
Another such day is inserted between June 31 and July 1 on leap years.
Grosclaude lists many business advantages to this.
Three monthly days important to businesses, the 1st, 15th, and 30th would always occur on the same 3 days of the week, respectively, and additionally would never occur on a Sunday, for example.
It became the model for The World Calendar, promoted by Elisabeth Acheils and The World Calendar Association since 1930.