\usepackage[greek.ancient,english]{babel}
\babeltags{grc = greek}
-% uncomment for testing:
-% \babelfont{rm}[Path = otf/,
-% ItalicFont={OldStandard-Italic.otf},
-% BoldFont={OldStandard-Bold.otf},
-% BoldItalicFont={OldStandard-BoldItalic.otf}]{OldStandard-Regular.otf}
-
-% \babelfont[greek]{rm}[Path = otf/,
-% RawFeature={+ss05;+ss06},
-% ItalicFont={OldStandard-Italic.otf},
-% BoldFont={OldStandard-Bold.otf},
-% BoldItalicFont={OldStandard-BoldItalic.otf}]{OldStandard-Regular.otf}
-
-% use the following two lines once Old Standard is installed:
\babelfont{rm}{Old Standard}
\babelfont[greek]{rm}[RawFeature={+ss05;+ss06}]{Old Standard}