The
Grand March in
Aida was written for trumpets in
B natural and
A flat, which are (I'm no musician, but I'm led to understand) a bit unusual for trumpets. Decades later,
Tutankhamun's
tomb was opened and among the contents transferred to the
Cairo Museum were two trumpets in just those keys. There exists a
recording of a British military trumpeter playing one. It does indeed sound
weird, and perfect for the effect in
Aida.
This recording was presumably made in the 1930s. I don't know whether the trumpeter made it through the War.