Prussian presumably as that is where he was from. According to wikipedia he used to say he was born in Königsberg but there is a possibility he was born in anot

Prussian presumably as that is where he was from. According to wikipedia he used to say he was born in Königsberg but there is a possibility he was born in another place near there. [1] [1] https://en.wikipedia.org/wiki/David_Hilbert https://en.wikipedia.org/wiki/David_Hilbert