Ostinato fantasia. Work becomes increasingly loose as it progresses. The work doesn’t really stand up to sectionalization >> my analysis is only functional to show melodic ideas. Several of the sub-themes are derived from the ostinato: Numbers 2 + 4.
Ostinato is introduced imitatively at beginning A – T – B – free – B – K (f)
S enters at 18 – S – T – A – free – K (Bb). Common for Narvaez not to enter 4th voice until after 1st Cadence.
Theme 2 introduced at 36 (g) and given in 8va voice pairs S/A – T/B – 3rd statement quickly dissipates into free polyphony, then approaching the cadence (from 56) a string of sequenced suspensions is used (ct. Baroque style) >> K (F). Sequences then repeated, and at 70, compases 15-18 are restated giving rise to another sequential string of theme 3, with sequential movement in lower & middle parts too >> K (F) at 81.
Theme 4 introduced, variant of Ostinato. Given as canon a 2. Then becoming free counterpoint from about 90 until end.
No move thematic statement, consonancia y redobles texture (somewhat) at 101 >> At 121 a repeat is made of preceding phrase and followed by final K (F) at 128.
Compas III is 6/4 metre, shown in source with time signature changes.

This fantasia was modified and reprinted by Venegas de Henestrosa, Libro de cifra nueva, fol. 39v (Brown 1557-02, no 67) [Anglés edition, pp. 95-97, Fantasia XIII].