Calendar and holiday calculations
Calendar grids use UTC-based Gregorian date functions so output does not depend on the server time zone. Federal holiday rules follow 5 U.S.C. § 6103 and US Office of Personnel Management guidance. Actual holiday dates and substitute observed weekdays are stored separately. Easter uses the standard Gregorian computus; astronomical values use documented algorithms and are labeled with their time-zone assumptions.
Historical research standard
Event articles prefer primary records and authoritative institutions: government archives, official organizations, universities, museums, peer-reviewed work and established news services. Wikipedia can help locate a lead but is not treated as sufficient evidence on its own. Each published article lists the sources used.
Original writing and editorial review
We do not copy competitor text, spin source paragraphs or publish synonymized versions of other pages. Date automation is used for repeatable calculations and validation, not as a substitute for reporting. Every indexable article must follow the Old Calendars voice, trace factual claims to its listed sources and pass a line edit that removes generic filler, repeated phrasing and unsupported conclusions. Pages without enough editorial value stay out of search indexing until the work is complete.
Corrections
If you find an error, email oldcalenders@gmail.com with the page URL, the statement you believe is wrong and a reliable source when possible. We review factual corrections promptly, update the page date and fix shared code when the error affects more than one year.
Who is responsible
Old Calendars was created by Naveed Qadir, a software engineer who builds web and mobile apps. Naveed Qadir is responsible for the site, its calendar engine and its corrections. Research, writing and review follow the standards on this page. Read more on the About page.
Advertising independence
Advertising can fund the site but does not decide which holidays or historical events are included. Ads are visually separated from editorial content. We do not sell favorable coverage or allow an advertiser to rewrite factual conclusions.