\usepackage{unicode-math}
\setmainfont{OldStandard}[
Extension=.otf,
UprightFont=*-Regular,
ItalicFont=*-Italic,
BoldFont=*-Bold,
BoldItalicFont=*-BoldItalic,
SmallCapsFeatures={Numbers=OldStyle},
FakeBold=0.1
]
\setmathfont{OldStandard-Math.otf}[FakeBold=1]
