This is a manuscript created by William Byrd, and is often considered one of the most important Renaissance keyboard collections.  It was put together as his 42 best works for keyboard, with some notable pieces including The Passinge Mesures Pavian and Galliarde and Have with yow to Walsingame.  It was often said that these compositions were an incredible inspiration to Johann Bach and Beethoven, and that this collection is one of the first to really leave an impact on Western music.  It is also fascinating because these pieces show a transition of style.  The earlier music shows his polyphonic counterpoint style, but then transitions to the demanding, energetic, rhythmically intensive pieces of his later pieces. Image source: Amazon