+@code{\override Staff.Accidental #'glyph-name-alist =
+#alteration-mensural-glyph-name-alist}
+
+@seealso
+
+Notation Reference: @ref{Pitches}, @ref{Accidentals}, and
+@ref{Automatic accidentals} give a general introduction of the use of
+accidentals. @ref{Key signature} gives a general introduction of
+the use of key signatures.
+
+Internals Reference: @rinternals{KeySignature}.
+
+@c {{{2 Annotational accidentals (musica ficta)
+@node Annotational accidentals (musica ficta)
+@unnumberedsubsubsec Annotational accidentals (@emph{musica ficta})
+
+In European music from before about 1600, singers were expected to
+chromatically alter notes at their own initiative according to
+certain rules. This is called @notation{musica ficta}. In modern
+transcriptions, these accidentals are usually printed over the
+note.
+
+@cindex Accidental, musica ficta
+@cindex Musica ficta
+
+Support for such suggested accidentals is included, and can be
+switched on by setting @code{suggestAccidentals} to true.
+
+@funindex suggestAccidentals
+
+@lilypond[verbatim,fragment,relative=1]
+fis gis
+\set suggestAccidentals = ##t
+ais bis
+@end lilypond
+
+This will treat @emph{every} subsequent accidental as @emph{musica
+ficta} until it is unset with @code{\set suggestAccidentals =
+##f}. A more practical way is to use @code{\once \set
+suggestAccidentals = ##t}, which can even be defined as a
+convenient shorthand:
+
+@lilypond[quote,verbatim]
+ficta = { \once \set suggestAccidentals = ##t }
+\score { \relative c''
+ \new MensuralVoice {
+ \once \set suggestAccidentals = ##t
+ bes4 a2 g2 \ficta fis8 \ficta e! fis2 g1
+ }
+}
+@end lilypond
+
+@seealso
+
+Internals Reference: @rinternals{Accidental_engraver} engraver and
+the @rinternals{AccidentalSuggestion} object.
+
+
+@c {{{2White mensural ligatures
+@node White mensural ligatures
+@unnumberedsubsubsec White mensural ligatures
+
+@cindex Mensural ligatures
+@cindex White mensural ligatures
+
+There is limited support for white mensural ligatures.
+
+To engrave white mensural ligatures, in the layout block, replace
+the @rinternals{Ligature_bracket_engraver} with the
+@rinternals{Mensural_ligature_engraver} in the @rinternals{Voice}
+context:
+
+@example
+\layout @{
+ \context @{
+ \Voice
+ \remove Ligature_bracket_engraver
+ \consists Mensural_ligature_engraver
+ @}
+@}
+@end example
+
+There is no additional input language to describe the shape of a
+white mensural ligature. The shape is rather determined solely from
+the pitch and duration of the enclosed notes. While this approach may
+take a new user a while to get accustomed to, it has the great advantage
+that the full musical information of the ligature is known internally.
+This is not only required for correct MIDI output, but also allows for
+automatic transcription of the ligatures.
+
+For example,
+
+@c @example
+@c \set Score.timing = ##f
+@c \set Score.defaultBarType = "empty"
+@c \override NoteHead #'style = #'neomensural
+@c \override Staff.TimeSignature #'style = #'neomensural
+@c \clef "petrucci-g"
+@c \[ c'\maxima g \]
+@c \[ d\longa c\breve f e d \]
+@c \[ c'\maxima d'\longa \]
+@c \[ e'1 a g\breve \]
+@c @end example
+@lilypond[quote,ragged-right,verbatim]
+\score {
+ \transpose c c' {
+ \set Score.timing = ##f
+ \set Score.defaultBarType = "empty"
+ \override NoteHead #'style = #'neomensural
+ \override Staff.TimeSignature #'style = #'neomensural
+ \clef "petrucci-g"
+ \[ c'\maxima g \]
+ \[ d\longa c\breve f e d \]
+ \[ c'\maxima d'\longa \]
+ \[ e'1 a g\breve \]
+ }
+ \layout {
+ \context {
+ \Voice
+ \remove Ligature_bracket_engraver
+ \consists Mensural_ligature_engraver
+ }
+ }
+}
+@end lilypond
+
+Without replacing @rinternals{Ligature_bracket_engraver} with
+@rinternals{Mensural_ligature_engraver}, the same music transcribes
+to the following
+
+@lilypond[quote,ragged-right]
+\transpose c c' {
+ \set Score.timing = ##f
+ \set Score.defaultBarType = "empty"
+ \override NoteHead #'style = #'neomensural
+ \override Staff.TimeSignature #'style = #'neomensural
+ \clef "petrucci-g"
+ \[ c'\maxima g \]
+ \[ d\longa c\breve f e d \]
+ \[ c'\maxima d'\longa \]
+ \[ e'1 a g\breve \]
+}
+@end lilypond
+
+@seealso
+
+TODO: nothing here yet ...
+
+@knownissues
+
+Horizontal spacing is poor.
+
+
+@c {{{1 Typesetting Gregorian chant
+@node Typesetting Gregorian chant
+@subsection Typesetting Gregorian chant
+
+@menu
+* Gregorian chant contexts::
+* Gregorian clefs::
+* Gregorian accidentals and key signatures::
+* Divisiones::
+* Gregorian articulation signs::
+* Augmentum dots (@emph{morae})::
+* Gregorian square neume ligatures::
+@end menu
+
+When typesetting a piece in Gregorian chant notation, the
+@rinternals{Vaticana_ligature_engraver} automatically selects the
+proper note heads, so there is no need to explicitly set the note
+head style. Still, the note head style can be set, e.g., to
+@code{vaticana_punctum} to produce punctum neumes. Similarly, the
+@rinternals{Mensural_ligature_engraver} automatically assembles
+mensural ligatures. See @ref{Ligatures}, for how ligature
+engravers work.
+
+
+@c {{{2Gregorian chant contexts
+@node Gregorian chant contexts
+@unnumberedsubsubsec Gregorian chant contexts
+
+@cindex VaticanaVoiceContext
+@cindex VaticanaStaffContext
+
+The predefined @code{VaticanaVoiceContext} and
+@code{VaticanaStaffContext} can be used to engrave a piece of
+Gregorian chant in the style of the Editio Vaticana. These contexts
+initialize all relevant context properties and grob properties to
+proper values, so you can immediately go ahead entering the chant, as
+the following excerpt demonstrates:
+
+@lilypond[quote,ragged-right,packed,verbatim]
+\include "gregorian.ly"
+\score {
+ <<
+ \new VaticanaVoice = "cantus" {
+ \[ c'\melisma c' \flexa a \]
+ \[ a \flexa \deminutum g\melismaEnd \]
+ f \divisioMinima
+ \[ f\melisma \pes a c' c' \pes d'\melismaEnd \]
+ c' \divisioMinima \break
+ \[ c'\melisma c' \flexa a \]
+ \[ a \flexa \deminutum g\melismaEnd \] f \divisioMinima
+ }
+ \new Lyrics \lyricsto "cantus" {
+ San- ctus, San- ctus, San- ctus
+ }
+ >>
+}
+@end lilypond
+
+@seealso
+
+TODO: nothing here yet ...
+
+@c {{{2 Gregorian clefs
+@node Gregorian clefs
+@unnumberedsubsubsec Gregorian clefs
+
+@cindex clefs
+
+The following table shows all Gregorian clefs that are supported via
+the @code{\clef} command. Some of the clefs use the same glyph,
+but differ only with respect to the line they are printed on. In
+such cases, a trailing number in the name is used to enumerate
+these clefs, numbered from the lowest to the highest line. Still,
+you can manually force a clef glyph to be typeset on an arbitrary
+line, as described in @ref{Clef}. The note printed to the right
+side of each clef in the example column denotes the @code{c'} with
+respect to that clef.
+
+@multitable @columnfractions .4 .4 .2
+@item
+@b{Description}
+@tab
+@b{Supported Clefs}
+@tab
+@b{Example}
+
+@item
+Editio Vaticana style do clef
+@tab
+@code{vaticana-do1}, @code{vaticana-do2},@*
+@code{vaticana-do3}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'vaticana.punctum
+ \clef "vaticana-do2"
+ c
+@end lilypond
+
+@item
+Editio Vaticana style fa clef
+@tab
+@code{vaticana-fa1}, @code{vaticana-fa2}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'vaticana.punctum
+ \clef "vaticana-fa2"
+ c
+@end lilypond
+
+@item
+Editio Medicaea style do clef
+@tab
+@code{medicaea-do1}, @code{medicaea-do2},@*
+@code{medicaea-do3}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'medicaea.punctum
+ \clef "medicaea-do2"
+ c
+@end lilypond
+
+@item
+Editio Medicaea style fa clef
+@tab
+@code{medicaea-fa1}, @code{medicaea-fa2}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'medicaea.punctum
+ \clef "medicaea-fa2"
+ c
+@end lilypond
+
+@item
+hufnagel style do clef
+@tab
+@code{hufnagel-do1}, @code{hufnagel-do2},@*
+@code{hufnagel-do3}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'hufnagel.punctum
+ \clef "hufnagel-do2"
+ c
+@end lilypond
+
+@item
+hufnagel style fa clef
+@tab
+@code{hufnagel-fa1}, @code{hufnagel-fa2}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'line-count = #4
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'hufnagel.punctum
+ \clef "hufnagel-fa2"
+ c
+@end lilypond
+
+@item
+hufnagel style combined do/fa clef
+@tab
+@code{hufnagel-do-fa}
+@tab
+@lilypond[fragment,relative=1,notime]
+ \override Staff.StaffSymbol #'color = #red
+ \override Staff.LedgerLineSpanner #'color = #red
+ \override Voice.Stem #'transparent = ##t
+ \override NoteHead #'style = #'hufnagel.punctum
+ \clef "hufnagel-do-fa"
+ c
+@end lilypond
+@end multitable
+
+@seealso
+
+Notation Reference: see @ref{Clef}.
+
+@c {{{2 Gregorian accidentals and key signatures
+@node Gregorian accidentals and key signatures
+@unnumberedsubsubsec Gregorian accidentals and key signatures
+
+@cindex accidentals
+@cindex key signature
+
+Accidentals for the three different Gregorian styles are available:
+
+@lilypond[quote,ragged-right,staffsize=26]
+\score {
+{
+ \textLengthOn
+ s^\markup {
+ \column {
+ "vaticana"
+ \line { " " \musicglyph #"accidentals.vaticana-1"
+ " " \musicglyph #"accidentals.vaticana0" }
+ }
+ \column {
+ "medicaea"
+ \line { " " \musicglyph #"accidentals.medicaea-1" }
+ }
+ \column {
+ "hufnagel"
+ \line { " " \musicglyph #"accidentals.hufnagel-1" }
+ }
+ }
+}
+\layout {
+ interscoreline = 1
+ \context { \Score \remove "Bar_number_engraver" }
+ \context { \Staff
+ \remove "Clef_engraver"
+ \remove "Key_engraver"
+ \remove "Time_signature_engraver"
+ \remove "Staff_symbol_engraver"
+ \override VerticalAxisGroup #'minimum-Y-extent = ##f
+ }
+ }
+}
+@end lilypond
+
+As shown, not all accidentals are supported by each style. When
+trying to access an unsupported accidental, LilyPond will switch to a
+different style.
+
+@c @lilypondfile[verbatim,lilyquote,texidoc,doctitle]
+@c {ancient-accidentals.ly}
+
+The style for accidentals and key signatures is controlled by the
+@code{glyph-name-alist} property of the grobs @rinternals{Accidental} and
+@rinternals{KeySignature}, respectively; e.g.:
+
+@code{\override Staff.Accidental #'glyph-name-alist =
+#alteration-mensural-glyph-name-alist}
+
+@seealso
+
+Notation Reference: @ref{Pitches}, @ref{Accidentals}, and
+@ref{Automatic accidentals} give a general introduction of the use of
+accidentals. @ref{Key signature} gives a general introduction of
+the use of key signatures.
+
+Internals Reference: @rinternals{KeySignature}.
+
+@c {{{2Divisiones
+@node Divisiones
+@unnumberedsubsubsec Divisiones
+
+@cindex divisio
+@cindex divisiones
+@cindex finalis
+
+A @emph{divisio} (plural: @emph{divisiones}; Latin word for
+@q{division}) is a staff context symbol that is used to indicate
+the phrase and section structure of Gregorian music. The musical meaning of
+@emph{divisio minima}, @emph{divisio maior}, and @emph{divisio maxima}
+can be characterized as short, medium, and long pause, somewhat like
+the breathmarks from @ref{Breath marks}. The @emph{finalis} sign not
+only marks the end of a chant, but is also frequently used within a
+single antiphonal/responsorial chant to mark the end of each section.
+
+To use divisiones, include the file @file{gregorian@/-init@/.ly}. It
+contains definitions that you can apply by just inserting
+@code{\divisioMinima}, @code{\divisioMaior}, @code{\divisioMaxima},
+and @code{\finalis} at proper places in the input. Some editions use
+@emph{virgula} or @emph{caesura} instead of divisio minima.
+Therefore, @file{gregorian@/-init@/.ly} also defines @code{\virgula} and
+@code{\caesura}
+
+@lilypondfile[quote,ragged-right]{divisiones.ly}
+
+@predefined
+
+@funindex \virgula
+@code{\virgula},
+@funindex \caesura
+@code{\caesura},
+@funindex \divisioMinima
+@code{\divisioMinima},
+@funindex \divisioMaior
+@code{\divisioMaior},
+@funindex \divisioMaxima
+@code{\divisioMaxima},
+@funindex \finalis
+@code{\finalis}.
+
+
+@c {{{2Gregorian articulations
+@node Gregorian articulation signs
+@unnumberedsubsubsec Gregorian articulation signs
+
+@cindex articulations
+
+In addition to the standard articulation signs described in
+section @ref{Articulations and ornamentations}, articulation signs
+specifically designed for use with notation in @emph{Editio
+Vaticana} style are provided.
+
+@lilypond[quote,ragged-right,verbatim]
+\include "gregorian.ly"
+\score {
+ \new VaticanaVoice {
+ \override TextScript #'font-family = #'typewriter
+ \override TextScript #'font-shape = #'upright
+ \override Script #'padding = #-0.1
+ a\ictus_"ictus " \break
+ a\circulus_"circulus " \break
+ a\semicirculus_"semicirculus " \break
+ a\accentus_"accentus " \break
+ \[ a_"episema" \episemInitium \pes b \flexa a b \episemFinis \flexa a \]
+ }
+}
+@end lilypond
+
+@seealso
+
+TODO: nothing here yet ...
+
+@knownissues
+
+Some articulations are vertically placed too closely to the
+corresponding note heads.
+
+The episema line is not displayed in many cases. If it is displayed,
+the right end of the episema line is often too far to the right.
+
+
+@c {{{2Augmentum dots (@emph{morae})
+@node Augmentum dots (@emph{morae})
+@unnumberedsubsubsec Augmentum dots (@emph{morae})
+
+Augmentum dots, also called @emph{morae}, are added with the music
+function @code{\augmentum}. Note that @code{\augmentum} is
+implemented as a unary music function rather than as head prefix. It
+applies to the immediately following music expression only. That is,
+@code{\augmentum \virga c} will have no visible effect. Instead, say
+@code{\virga \augmentum c} or @code{\augmentum @{\virga c@}}. Also
+note that you can say @code{\augmentum @{a g@}} as a shortcut for
+@code{\augmentum a \augmentum g}.