ΔE 12.9, fair: the same colour family, but not a straight swap. Battle of Marathon is noticeably lighter, more muted than Dryad Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Battle of Marathon is noticeably lighter, more muted than Dryad Brown.
The same difference applies the other way round: Dryad Brown is noticeably darker, more saturated.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Dryad Brown on the colour wheel See Battle of Marathon on the colour wheel
All matches: Dryad Brown equivalents · Battle of Marathon equivalents