Date sequence in R spanning B.C.E. to A.D

I would like to generate a sequence of dates from 10,000 B.C.E. to the present. This is easy for 0 C.E. (or A.D.):

ADtoNow <- seq.Date(from = as.Date("0/1/1"), to = Sys.Date(), by = "day")

But I am stumped as to how to generate dates before 0 AD. Obviously, I could do years before present but it would be nice to be able to graph something as BCE and AD.