Not only did cryptography exist in ancient Greece and Rome, but the fundamental design and principles of ancient cryptographic devices such as the Spartan Skytale and the Caesar Cipher set the foundation for contemporary encryption algorithms. Accordingly, knowledge of these devices survived throughout Late Antiquity and the Middle Ages, and reappeared during the Renaissance in new inventions such as the Alberti Cipher. Through the analysis of accounts by Aulus Gellius, Aeneas Tacticus, Suetonius, and Leon Battista Alberti, this thesis will examine how these ciphers are defined as cryptographical devices and examine several critical components they share with contemporary cryptographic algorithms.