Ancient Rome was a civilization that existed in parts of Europe, Africa, and Asia. Its territory was so expansive that Shakespeare has one of his characters call it "[t]he three-fold world divided" and Cato's Letters write, of Julius Caesar's usurpation of power, "he seized the world, and extinguished its liberty." According to Ludwig von Mises, "What brought about the decline of the empire and the decay of its civilization was the disintegration of this economic interconnectedness, not the barbarian invasions."
- "The Tragedy of Julius Caesar (unsourced edition)/Act IV". https://en.wikisource.org/wiki/The_Tragedy_of_Julius_Caesar_%28unsourced_edition%29/Act_IV.
- "Cato's Letter No. 55: The Lawfulness of killing Julius Caesar considered, and defended, against Dr. Prideaux". https://en.wikisource.org/wiki/Cato%27s_Letter_No._55.
- Mises, Ludwig von. "Human Action". http://mises.org/humanaction/chap30sec2.asp.