\defaultfontfeatures{Ligatures=TeX}
\setmainfont[%
  Script=Default,% make small caps work for both latn and grek
         ItalicFont=STIXTwoText-Italic.otf,
	 BoldFont=STIXTwoText-Bold.otf,
	 BoldItalicFont=STIXTwoText-BoldItalic.otf,
         % RawFeature=+pnum,% variable width numbers
SmallCapsFeatures={Numbers=OldStyle}]{STIXTwoText-Regular.otf}
\setmathfont{STIXTwoMath-Regular.otf}