"The House of the Sphinx" by Lord Dunsany

I feel like this story has some level of abstraction beyond the bare facts presented, but I'm not sure what. I wonder if there could be some form of autobiographical aspect to it? I don't know anything about Lord Dunsany so I have no idea, but this is a rather odd tale otherwise.

Or perhaps it is just the retelling of a dream he once had?

I don't understand the phrase "this person was quite white". I'm assuming that's not a reference to race, but then to what? Is this anything like Machen's "The White People"?

The picture used is an illustration by Sidney Sime in the 1912 edition of "The Book of Wonder".

To follow along: https://www.gutenberg.org/files/7477/7477-h/7477-h.htm#THE_HOUSE_OF_THE_SPHINX