\RequirePackage{fontspec}
\defaultfontfeatures{Ligatures=TeX}

\setmainfont[%
ItalicFont=OldStandard-Italic.otf,
BoldFont=OldStandard-Bold.otf,
BoldItalicFont=OldStandard-BoldItalic.otf,
SmallCapsFeatures={Numbers=OldStyle}]{OldStandard-Regular.otf}



\RequirePackage{unicode-math}
\setmathfont{Garamond-Math.otf}
\setmathfont[range=\mathup/{num,latin,Latin,greek,Greek}]{OldStandard-Regular.otf} 
\setmathfont[range=\mathbfup/{num,latin,Latin,greek,Greek}]{OldStandard-Bold.otf} 
\setmathfont[range=\mathit/{num,latin,Latin,greek,Greek}]{OldStandard-Italic.otf} 
\setmathfont[range=\mathbfit/{num,latin,Latin,greek,Greek}]{OldStandard-BoldItalic.otf}


\endinput