the amans use a christian calendar.
No. There is the Gregorian calendar (used by Americans, Europeans, and Japanese), a Hebrew calendar, and a Muslim calendar at least. Here's a link to a Chinese calendar and an Indian calendar.
Spaniards use the Gregorian Calendar just like US Americans and Britons. It starts on January 1st.
Gregorian Calendar!
They used the Egyptian Calender.
A perpetual calendar is the type of calendar that can be adjusted for any year. This type of calendar can be reused each year.
An agrarian calendar is a farming calendar. School's still use this type of calendar, it is based on planting, and harvesting. This is why schools had summer vacation. Summer was when children were needed at home to help with farming.
The Aztec calendar recognised 365 days
They brought the calendar with them from Europe.
It was the Roman calendar.
The new calendar has pictures
The Gregorian calendar.
the Gregorian calendar