Not a historian or anything, but how cool is it to respond to a 25-year old post!
In "Gentleman's Book of Etiquete" by Cecil B. Hartley (published 1860), in Chapter II - Politeness, it says:

“There is no country in the world where the absurdities of etiquette are carried to so great a length as in Spain, because there is no nation where the nobility are so proud. The following anecdote, which illustrates this, would seem incredible were it not a historical fact:

'Philip the Third, king of Spain, was sick, and being able to sit up, was carefully placed in an arm chair which stood opposite to a large fire, when the wood was piled up to an enormous height. The heat soon became intolerable, and the courtiers retired from around the king; but, as the Duke D’Ussede, the fire stirrer for the king, was not present, and as no one else had the right to touch the fire, those present dared not attempt to diminish the heat. The grand chamberlain was also absent, and he alone was authorized to touch the king’s footstool. The poor king, too ill to rise, in vain implored those around him to move his chair, no one dared touch it, and when the grand chamberlain arrived, the king had fainted with the heat, and a few days later he died, literally roasted to death.' ”

I don't know how much of this is true but it's silly that even in 2021 it seems difficult to find the cause of a king's death. For anyone interested, the whole book is here: https://www.gutenberg.org/files/39293/39293-h/39293-h.htm