Information about Siese is primarily derived from his mastaba, which was excavated by Jacques de Morgan around 1894/5 at Dahshur and rediscovered in 2008 by an Egyptian team. The mastaba was decorated with a palace facade and with scenes showing Siese and his family. Four panels with the image of Siese in front of an offering table were excavated by de Morgan and are now on display in the Egyptian Museum of Cairo.