ABC Wednesday, C for Calendar

Almost every year around Christmas I get one or more calenders.This year my eldest daughter made me one, which was a lovely surprise. She is a technical designer, who has to draw machinery and engines for an American factory. Last year they made a huge engine for New York for recycling all kind of plastic of the whole city. But in her spare time she draws illustrations for among other things, calenders. One of them is the one my daughter made.

A selfie of my daughter

A number of prehistoric structures have been proposed as having had the purpose of timekeeping (typically keeping track of the course of the solar year). This includes many megalithic structures, and reconstructed arrangements going back far into the Neolithic period.

A mesolithic arrangement of twelve pits and an arc found in Warren Field, Aberdeenshire, Scotland, dated to roughly 10,000 years ago, has been described as a lunar calendar and dubbed the "world's oldest known calendar" in 2013

January

Most of the oldest calendars were lunar calendars, based on the time interval from one new moon to the next—a so-called lunation. But even in a warm climate there are annual events that pay no attention to the phases of the Moon. In some areas it was a rainy season; in Egypt it was the annual flooding of the Nile River. The calendar had to account for these yearly events as well.

• History of the Lunar Calendar
• History of the Egytpian Calendar
• History of the Roman (Julian) Calendar
• History of the Gregorian Calendar
• Adoption of the Gregorian Calendar

With thanks to Denise Nesbitt, who created the ABC meme.For more interesting ABC posts click on the logo in the sidebar . This week we are looking for words beginning with C and then we will have begun Round Eighteen