Last weekend we were staying near Siena for a wedding (my husband’s cousin) in the city, and while we were there we took the opportunity to visit the cathedral. It’s a beautiful building, though quite different to the plain unpainted cathedrals of England, being more full of art than light (perhaps better suited to the Italian climate, though!), and fantastically striped black and white. In the Duomo itself were statues by Michelangelo, and in the Battistera bronzes by Ghiberti, and other artists.
However, what was most astonishing and at which we spent a long time looking, were the choir books of the Piccolomini Library. The room is a riot of colour, both from the painted walls and celing, but also because of the open choir books, displayed in the glass-fronted display cases, which are beautifully illuminated. They also seem to be in fantastic condition, too.
The choir books give the tunes for the sung portions of the daily services, and although the chant is quite easy to read, the Latin isn’t (though mediaevalists are probably used to all the letters looking the same). Since they’re so decorative, I do wonder if they were used very often: the size seems to indicate that the singers would have gathered around them.
I don’t know enough Latin (nor, indeed, am familiar enough with the old rite) to determine if the detailed illustrations relate to the words to be sung or the appointed readings for the day. Aren’t they beautiful?
Ela's Book Blog 
Yes, they are beautiful. Illuminated manuscripts are great. I can help feeling that the Renaissance represented a wrong turning in visual art.
I’d have liked the two trends to coexist – I wouldn’t want to be without, say, Michelangelo’s sculpture, but there’s a lot to admire in earlier art which, if it isn’t always fully representational, is packed with spiritual meaning.
Though I’ve visited Siena once many years, I didn’t know these MSS were on display — they probably weren’t at that time. Yes, I’m certain they were meant for several people to pore over. I’m more familiar with facsimiles of lute songs (which I used to perform badly in folk clubs); these were designed to be displayed flat with the vocal part on the left hand page and the lute part and bass viol part arranged on the right hand page so that the instrumentalists were virtually facing the singer in order to read the music. The lute books, printed in black and white, weren’t anywhere near as colourful as these illuminated manuscripts!
Decoration in churches: it’s easy to forget that with the Reformation and later Puritan influences in Britain most of the wall paintings on plaster in Britain were obliterated with whitewash, and what was thus hidden from view was often later removed wholesale by Victorians either dealing with centuries of damp or removing the plaster to reveal the “beautiful” stonework beneath, stonework rarely actually exposed in the Middle Ages. Occasionally we’re lucky enough to see frescoes that have survived when whitewash has been painstakingly removed or when wall memorials have been taken down or wood panelling replaced.
I had previously visited Siena and didn’t recall having seen those books on the previous visit, so maybe they’d been undergoing intensive conservation and were only just returned to display. I’ve seen some part books in Worcester cathedral library, but not anything where all parts of the polyphony are written out. And of course, the Reformation led to a lot of Catholic rite being destroyed, which is why the Eton Choir Book is so important in the study of pre-Reformation music in England.
What I found particularly striking at Siena was the relative lack of windows, in comparison to an English cathedral (as well the humbug-striped interior!).