Calendars and Timelines

General

• Calendar
  By Eric Weisstein. Part of his great Treasure Trove of Astronomy.
• Calendars and Their History
  Reprinted from the Explanatory Supplement to the Astronomical Almanac.
• Calendar Studies
  Peter Meyer's articles on the Gregorian and Julian calendars, the ISO date format, the Julian day number system, C functions for date conversion, the Maya calendar and the Goddess Lunar Calendar plus software for calendrical conversion.
• English Calendar
• The Moon
  Current information on moon phases.

Perpetual Calendars

• The Perpetual Calendar
  Toke Norby's helpful Tool to Postal Historians. Emphasizes dates of change from one calendar reckoning to another - especially Julian to Gregorian - in various locations.
• Virtual Perpetual Calendars

Religious Calendars:

• Calculation of the Ecclesiastical Calendar
• Calendar of Jewish Holidays [Union of American Hebrew Congregations]
• Ecclesiastical Calendar Conversion

Subject Calendars

• AlternaTime
  A collection of timelines on the web.
• Anyday
  Historic events and birthdates that occurred on a selected day of the year.
• Chronology of U.S. Historical Documents
  Includes links to texts.
• Hobbes' Internet Timeline
• Romantic Chronology
  A chronology of events during the English Romantic period with links to texts.
• Space Calendar
  Space-related activities and anniversaries for the coming year, including over 1,000 links to related home pages.