Mesoamerican calendars was of ritual significance to a number of Mesoamerican cultures. A third major calendar form known as the Long Count is found in the inscriptions of several Mesoamerican cultures, most famously those of the Maya civilization who developed it to its fullest extent during the Classic period (ca. 200–900 CE). The Long Count provided the ability to uniquely identify days over a much longer period of time, by combining a sequence of day-counts or cycles of increasing length, calculated or set from a particular date in the mythical past. Most commonly, five such higher-order cycles in a modified vigesimal (base-20)
The Calendar of Nature "The Months". The 1821 edition contained a preface which declared, "The good-nature with which this Calendar was received on its appearance in 1819 ... has induced its republication in a separate form, with considerable additions". The 1821 edition also included the final two stanzas of John Keats's poem "To Autumn" with the claim that "A living poet has happily personified autumn in some of the pleasantest shapes under which her servants appear". The work quotes Percy Bysshe Shelley and discusses the works of Edmund Spenser. The calendar also refers to Shelley regarding autumn when it states: "The poet still takes