Cicero's Museum is a building on P4M-328. Cicero works at the museum as a researcher and Jayem Seran works there as one of the security guards. The planet's Stargate was located in the museum until the year 2007. The Stargate was buried after SG-1's visit.
Exhibits in Cicero's Museum included replicas of Ra's headdress, the helmet of a Horus Guard and the uniform of a Serpent Guard. This would seem to indicate that P4M-328 was under the control of both Ra and Apophis at different times in its history. (SG1: "Bad Guys")