Found by Googling "Easter 1680": http://www.easterbunny.com/date-of-easter/easter-date-for-16...
"For the year 1680 Easter's date is 21 April 1680 by the Western Calendar.
"For the year 1680 Easter's date is 21 April 1680 by the Orthodox Calendar.
"If you are curious about the date for the Julian calendar as a historical note:
For the year 1680 Easter's date is 11 April 1680 by the Julian Calendar.
"[Before the year 1583 the Julian calendar was the only one used, therefore before 1583, all dates are identical and are under the Julian Calendar.]"