The calendar that we use today is called the Gregorian calendar, created by Pope Gregory XIII. Before that, there was the Roman calendar, which was a lunar calendar, comprising 10 months and an intercalated month. Next came the Julian calendar, a twelve-month solar calendar introduced by Julius Caesar in 46 bc, consisting of 365 days, with an extra day every four years.
The Mayans, Egyptians, Babylonians, and Chinese all had calendars in the ancient days.
The calendar we use to today was first developed by the Romans, under Julius Caesar (the Julian Calendar). That was modified by the Gregorian Calendar (named for Pope Gregory XIII), which we still use today
Sumer, the birthplace of the modern sexagesimal system, there were 12 months of 29 or 30 days apiece, much like the modern Gregorian calendar. It took thousandths of years in history in the change of calendars.
Nobody knows who invented the first calendar because there are different calendars: the first calendar form appeared 20,500 BC, and probably was the lunar calendar.
Calendar: days
A calendar of 1991 can be found at calendarlabs.com
Calendar for 1989 can be found in calendarlabs.com
A reliable online sunrise and sunset calendar can be found in several places. One can be found on reliable calendar websites such as Calendar, Localendar, and many more sources.
Calendar for 1960 can be found at calendarlabs.com . You can get a calendar for any year in this website.
A calendar for 2015 can be found below the answer to this question.
Calendar for 2008 and 2009 can be found at www.calendarlabs.com .
September 2008 calendar can be found at www.calendarlabs.com .
1988
A link to a 1947 calendar can be found below the answer to this question.
A calendar for 2015 can be found below the answer to this question.
A calendar for June 1947 can be found below this answer.