The phrase "ancient principle" is correct and usable in written English.
You can use it when referring to a long-standing or traditional belief, rule, or guideline that has been accepted over time.
Example: "The ancient principle of justice has guided societies for centuries, influencing laws and moral codes."
Alternatives: "time-honored principle" or "long-standing principle".
Following an ancient principle, he jacked up the car in order to change the tire, whereupon the circular windshield cracked.
"The US is our natural friend … We believe in [the] ancient principle that the entire world … is a global family".
The problem here is that the ancient principle of Nimby (not in my back yard) becomes understandably universal.
The latest Islamic State video is proof, if it is needed, that Isis understands this ancient principle of warfare.
This ancient principle of defense, more than faith in the technology of radiation sensing, may explain the support that the Bush Administration's detector program has attracted so far.
Your description of Rupert Murdoch and Paul Dacre as "have-a-go heroes… charged with protecting Britain's ancient principle of freedom of speech" is laughable.
Hill's tips were based on the ancient principles of sympathetic magic: the idea that like counters like.
This work, he suggests, reflects trends that counter information overload, such as the widespread interest in "mindfulness" (a rehash of ancient principles of meditation).
The designs generated from these studies are simultaneously radical and traditional, unforeseen structures informed by ancient principles and the natural world.
"In many ways, we're going back to a lot of old, ancient principles, from societies in which the way you survived was by using everything around you," Choi said.
This restaurant, dedicated to ancient principles of Korean cuisine, is a shrine to the vegetarian impulse, with all the cleanness, lightness and purity so often attributed to it fully in evidence.
