We construct a covariant bound on the energy-momentum of the M-fivebrane
which is saturated by all supersymmetric configurations. This leads to a
generalised notion of a calibrated geometry for M-fivebranes when the
worldvolume gauge field is non-zero. The generalisation relevant for Dp-branes
is also given.Comment: 9 pages, LaTeX2e, uses vmargin.sty. Typos corrected, a reference and
a new discussion on conserved charges added. v4: A typo in the expression for
the D-fourbrane energy correcte
