Was Leonardo da Vinci a polyphasic sleeper?

Question

I have read from various (low quality) sources that Leonardo da Vinci practiced polyphasic sleep, maybe the Uberman's sleep schedule. Polyphasic sleep refers to the practice of sleeping multiple times in a 24-hour period—usually more than two, in contrast to biphasic sleep (twice per day) or monophasic sleep (once per day).

Yanko Design:

An object that with knowledge of the most excellent ways of Leonardo Da Vinci will require very little explaining. The Da Vinci Alarm Clock assists the user in adhering to the 3.5/.5 sleep schedule devised by the Renaissance Man, allowing the user 21 hours of awake time a day, completely free of sleepiness.

4-Hour Life

Become Uberman & Sleep like Da Vinci: The Polyphasic Sleep Cheat Sheet: this is supposedly the way that Leonardo Da Vinci, Thomas Jefferson, Matt Mullenweg (the developer of WordPress) and a fluctuating list of other legends (including Tim Ferriss) often slept.

However, some emit doubts:

Polyphasic Sleep: Facts and Myths:

Although even Stampi anecdotally refers to Leonardo da Vinci , Leonardo's polyphasic sleep is probably an urban myth. I could not locate any credible sources with any notes on his sleep habits, and yet da Vinci is nearly always mentioned whenever the art of napping comes into question. It seems quite strange that someone would come up with a crazy polyphasic schedule idea at the time of leisurely Renaissance life that was well-timed by the superiority of sunlight over candlelight. Allegedly, hinting at a monophasic mindset, he spoke of death: "As a well-spent day brings happy sleep, so a life well used brings happy death". Even more telling is Bandello's report on da Vinci's work over "The Last Supper". Leonardo would work continuously from dawn to dusk forgetting about food and drink. Stunned Bandello would definitely reported the round-the-clock work of a polyphasic sleeper as even more amazing. It seems to me that using a poorly researched historic case from 500 years ago as a prop in favor of polyphasic sleep is rather a dated argumentum ad verecundiam. Incidentally, da Vinci is also a name that crops up on other suspect lists: the lists of great people suffering from attention deficit disorder, or the lists of great vegetarians. The same memetic mechanism must be placing da Vinci, Jesus, Einstein, and Hitler alongside each other in a number of myths over and over again. And did you hear of "Da Vinci Code" or the authorship of the Turin Shroud?

Is there any trustworthy source indicating whether Leonardo da Vinci was a polyphasic sleeper?

Answer 1

Leonardi Da Vinci's notebooks are available.

We can see from this that he was not a fan of sleeping:

0 sleepers! what a thing is slumber! Sleep resembles death. Ah, why then dost thou not work in such wise as that after death thou mayst retain a resemblance to perfect life, when, during life, thou art in sleep so like to the hapless dead?

He also writes:

As a day well spent procures a happy sleep, so a life well employed procures a happy death.

There are no more direct mentions about 'sleep' in his notebooks except for fables and his observations which suggests that he really happened to think pessimistically about sleep, like all bad things happen during sleep. E.g.: A crocodile gets killed by a bird while it is asleep.

So, there is little evidence from his own notebooks of him experimenting with polyphasic sleep.