Diocletian's Palace in Split:

• http://www.st.carnet.hr/split/diokl.html
• http://metalab.unc.edu/expo/palace.exhibit/intro.html

Diagram about the Emperors of the Tetrarchy: http://www.salve.edu/~dimaiom/tetstem.html

Coins of Maximiano: http://artemis.austinc.edu/acad/cml/rcape/vcrc/3/Maximianus/vcrc.html