This is a linked open data (LOD) about date and time. "C.E. 1679 February 11" is a date of Gregorian Calendar (Calendar ID: 2.1).
http://datetime.hutime.org/calendar/2.1/date/C.E._1679_February_11
hcal:2.1/date/2334343.5
hcal:2.1/date/C.E._1679_February_11
hcaldate:2334343.5
hcaldate:C.E._1679_February_11