Adoption of the Gregorian calendar liege lord, the King of Poland, it agreed in 1611 to do so. So 22 August was followed by 2 September 1612. However, this calendar change did not apply for other territories of the Hohenzollern, such as Berlin-based Brandenburg, a fief of the Holy Roman Empire. Through Ole Rømer's influence, Denmark in 1700, which then included Norway, adopted the solar portion of the Gregorian calendar with Sunday, 18 February 1700, being followed by Monday, 1 March 1700, simultaneously with the Brandenburg-Pomerania and other Protestant estates of the Holy Roman Empire. None of these states adopted the lunar portion, instead calculating
Gregorian calendar the start of the year, and also aligned the British calendar with the Gregorian calendar, there is some confusion as to what these terms mean. They can indicate that the start of the Julian year has been adjusted to start on 1 January (NS) even though contemporary documents use a different start of year (OS); or to indicate that a date conforms to the Julian calendar (OS), formerly in use in many countries, rather than the Gregorian calendar (NS). Extending the Gregorian calendar backwards to dates preceding its official introduction produces a proleptic calendar, which should be used with some