What was the Spartans motto?

Could you elaborate on the significance of the Spartans' motto? It's intriguing to ponder what drove this ancient warrior society to adopt such a pithy yet powerful phrase as their guiding principle. Was it a testament to their unwavering determination, a call for unity amidst adversity, or perhaps a reminder of their strict code of conduct? What insights does this motto offer into the Spartan mindset and their place in history?