Palatino 766 pipes, pools, cliffs, streams... (by Taccola)

[Bernd]

On p.16, it is suggested that a copy must have been given to the emperor Sigismund in 1433.

On 13 January 1433, Taccola applied the finit to his book De ingeneis, obviously planning to give the work, or a copy of it, to Sigismund. Three months later the king departed from Siena, having completed his difficult negotiations and having exhausted if not overstayed his welcome at Siena; he had paid for her hospitality by ending the war with Florence and the Pope, an event to which Taccola alludes (IV 73v). The king was on his way to the usual ceremonial entry into Rome and to his coronation as Emperor. In the Eternal City he stayed a few months. He then proceeded back north, along the east coast of Italy. On 21 September 1433, he reached Mantua, his last major place of sojourn in Italy.
In this city he then, two days later, once more met a group of Sienese. They may have accompanied him bodily or, as is more probable, only in spirit and by messages, appearing now to take leave of him. According to the Regesta on 24 September, Marianus Jacobi "de Thomasinis," a term that was equivalent to the former de Humelis, and other Sienese men became comites palatini. No doubt the title was given in lieu of payment for some services rendered or properties delivered, and although the details again are not recorded, probably in Mariano's case the delivery of a copy of his book, personally or by proxy, was the occasion. However, no such copy is known to exist.

That's rather murky.
Between Taccola's completion of Book3+4 and Sigismund's departure were 3 months. Not a lot of time to make a fancy copy. He would have had 8 months until Sigismund's final departure from Italy which is more reasonable. Still there is no clear evidence this ever happened and if, we do not know which of his books (all4?) such a copy would have consisted of. I assume such a gift to the Emperor that was rewarded with a title would have been recorded somewhere. In any case, if Sigismund received a copy, he would have taken it back to Bohemia.