MuseScore offers several specialized functions to create engravings of early music (particularly medieval and renaissance) akin to commercial editions from the 20th century onwards.
In MuseScore, notes lasting longer than the duration of a measure are normally tied across barlines. However MuseScore has a special feature which allows it to display the note values intact, without splitting and tying them in this way. This enables you to notate music which is unbarred (i.e. not divided into measures), such as that of the renaissance:
Note: The feature is still in development and may contain bugs. The longest supported note value is the longa (a dotted longa is still broken up and tied over).
Since a complete lack of barlines could make performing the music more difficult for current musicians, many modern engravers settled on a compromise called Mensurstrich, where barlines are drawn between, but not across, staves.
To place barlines between staves:
Before there was the concept of an absolute pitch, performers were required to transpose vocal music to a singable range for their ensemble "on the fly." To aid them, an ambitus was sometimes included, marking the entire range of a voice at the beginning of the piece.
To apply an ambitus, use one of the following methods:
When applied, the ambitus automatically displays the note range of the score: if there is a section break then only the note range of the section is displayed. Beyond the section break a new ambitus may be applied.
The note range of the ambitus can be adjusted manually by selecting it and changing the "Top note" and "Bottom note" values in the Inspector. For automatic adjustment click the Update Range button in the inspector.
In the mensural notation system, time signatures did not define the length of a measure, but the length of breves and semibreves. MuseScore supports mensural time symbols as a display method in the Time signature properties dialog rather than as symbols, but they are just for show, as the proportion of e.g. half notes per whole notes cannot be modified.
One way to make use of these symbols is to replicate when composers of the renaissance had multiple voices in different time signatures simultaneously without using tuplets. Edit the time signature on a per-staff basis, as long as the beginning and end of a measure in all staves match up. If they do not, then consider increasing the size of the measures to the lowest common denominator.
De Profundis Clamavi for 5 voices by Josquin Des Prez