Font issues inside top-level markup

I’m trying to use italics with the Galliard font in a top-level markup and it’s not coming out right.  Instead of italic font, I get what looks like a bold version of a sans font (though not the one I specified in the paper block).

MWE:
\version "2.26.0"

\paper  {
    % Changing the lyric font (should match that of the document)
    property-defaults.fonts.serif = "Galliard"
    property-defaults.fonts.sans = "Hit the Road"
    property-defaults.fonts.typewriter = "Luxi Mono"
    
    #(set-paper-size "b5")
    
    oddFooterMarkup = ##f
}

\markup { \column {
    \concat { "Glory to God " \underline { "in" } " " \underline { "the" } " " \underline { "highest" } "," }
    "and on earth peace to people of good will."
    \italic { "[Omit C & D]” }
   % also tried
   %\override #'(font-name . "Galliard Italic") { "[Omit C & D]" }
}}

At the command line:

lilypond -dshow-available-fonts | grep Galliard
GNU LilyPond 2.26.0 (running Guile 3.0)
family Galliard
 Galliard:style=Bold
family Galliard
 Galliard:style=Italic
family Galliard
 Galliard:style=UltraItalic
family Galliard
 Galliard:style=Roman
family Galliard
 Galliard:style=BoldItalic
family Galliard
 Galliard:style=BlackItalic

What do I need to do to get Galliard’s italic font to be found and used correctly?

✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝
Fr. Samuel, OSB
(R. Padraic Springuel)
St. Anselm’s Abbey
4501 South Dakota Ave, NE
Washington, DC, 20017
202-269-2300
(c) 202-853-7036

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