Sustainability is a broad term that addresses three fundamental principles: economic strength, environmental stewardship, and social equity.
Renewable Energy: An Overview - Solar Architecture in Ancient Greece
Modern excavations of many Classical Greek cities show that solar architecture flourished throughout the area. Individual homes were oriented toward the southern horizon, and entire cities were planned to allow their citizens equal access to the winter sun. A solar-oriented home allowed its inhabitants to depend less on charcoal - conserving fuel and saving money.