Complex sentence: The Swedish calendar was a calendar in use in Sweden and its possessions from 1 March 1700 until 30 February 1712 (see below); it was one day ahead of the Julian calendar and ten days behind the Gregorian calendar.
Split into simpler sentences: The Swedish calendar was a calendar in use in Sweden and its possessions from 1 March 1700 until 30 February 1712 (see below). It was as one day ahead of the Julian calendar and ten days behind the Gregorian calendar.