This is a comparison of the man's portrait found on the wall behind the throne in Sirrus' chamber on Mechanical Age with the portrait of Napoleon I on his Imperial Throne, painted in 1806 by Jean Auguste Dominique Ingres. In the Myst version, the King's face is that of Sirrus.

You can see a larger version of the original portrait here at The Art Online web site.

Thanks to Peter Hargreaves for finding this and telling the Lysts about it! I've recently learned that Myro made an independent discovery of the same information.

Myst, Riven, and all things D'ni are the creation of Cyan Worlds, Inc.

The D'ni Desk Reference