diary-block

diary-block is a compiled Lisp function in `diary-lib.el'.

(diary-block M1 D1 Y1 M2 D2 Y2 &optional MARK)

Block diary entry.
Entry applies if date is between, or on one of, two dates. The order
of the input parameters changes according to `calendar-date-style'
(e.g. to D1, M1, Y1, D2, M2, Y2 in the European style).

An optional parameter MARK specifies a face or single-character string
to use when highlighting the day in the calendar.