Final answer:
True, after Aristotle, medieval theologians added faith, hope, and charity to the list of virtues, forming an integral part of Christian ethics that complemented ancient Greek virtues.
Step-by-step explanation:
After Aristotle, medieval theologians indeed supplemented the Greek list of virtues with three Christian ones, known as the theological virtues: faith, hope, and charity. This assertion is true. These virtues were considered foundational to Christian ethics and were meant to complement the philosophical virtues of antiquity, which included qualities such as courage, justice, temperance, and wisdom. The introduction of these Christian virtues represents a significant development in the history of ethical thought, blending ancient Greek philosophy with new Christian theological concepts.