Kalender
11 cards from across every topic, each citing a source. Tap one to open it in the feed.
- How our year count began, and why there's no year 0.
In 525, the monk Dionysius Exiguus in Rome wanted to calculate Easter tables and counted years from his estimate of …
- How the date of Easter is determined.
Easter falls on the first Sunday after the first full moon of spring, with spring fixed by the church at 21 March. That …
- How to put to-dos in your calendar instead of on lists.
With timeboxing you give each task a fixed time slot in your calendar in advance – say “report: Wednesday 9–11 a.m.”. …
- In 1582, ten days simply vanished from the calendar.
The Julian calendar ran about 11 minutes too long per year; by 1582 the spring equinox had drifted ten days. Pope …
- In 1712, Sweden had a 30th of February.
From 1700 Sweden tried to ease from Julian to Gregorian by skipping every leap day for 40 years. Then the Great …
- In Ethiopia the year has 13 months and the clock says 2018.
The Ethiopian calendar has twelve 30-day months plus a thirteenth, Pagume, of five or six days. New Year falls on 11 …
- In Portuguese, Monday is called "second day".
Almost every European language names weekdays after planets and gods: mardi after Mars, Thursday after Thor. Not …
- The world's largest annual human migration has a date.
Chinese New Year follows a lunisolar calendar and falls between 21 January and 20 February, on the second new moon …
- Why Jewish holidays start the evening before.
In the Hebrew calendar a day begins at sunset, not at midnight. The Sabbath therefore starts on Friday evening and ends …
- Why Ramadan starts eleven days earlier every year.
The Islamic calendar is purely lunar: twelve lunar months add up to about 354 days, eleven fewer than the solar year. …
- Why September means 'seventh month' but is the ninth.
The early Roman calendar began in March and had only ten months; winter was left unnamed. September, October, November …