"The Stoa is a living philosophy.  What that means is 
that Stoic philosophy is more than just great thoughts
organized into a complete and coherent vision of reality.  
It is first and foremost a philosophy to live by, a practical 
application of ancient wisdom, a way of life, and a guide 
to the choices one makes in this life.
"It also means something more.  The Stoa is alive.  The 
reason it is alive after nearly 2300 years is because it is 
universally adaptable and available to all people, men and 
women of every color, class, and culture.  And something 
else: it evolves.  As the human race learns and grows, so 
does the Stoa. It evolves because of the strength and 
conviction of the Stoics themselves. Stoics have a tradition 
of independent thought, and we like it that way.  We of the 
Stoic school, as Seneca said, do not follow a tyrant.  This 
is not to say that what we are left with is a hodgepodge of
assorted ideas collected here and there.  This is not the 
Stoa.  It's inner core of orthodoxy moves very slowly, 
glacially, expanding and refining with the ages.  Its 
foundation is secure because it is built upon the 
unassailable power of a single idea: Live according 
to nature.
"That's the Stoic motto.  Zeno of Citium said it first, and 
he's the founder and father of our school, but he wasn't 
working alone.  He was following a path already begun by 
two of the greatest thinkers in history, Heraclitus and 
Socrates.  These two men, one a mystic cosmologist and 
the other a moral philosopher who lived and died by his 
ideals, may rightly be called the Grandfathers of the Stoa.
"But Stoicism actually began with the teachings of Zeno 
at the central market of Athens about 300 BCE.  Zeno 
regularly met with students on the north side of the 
market at a stoa, a covered colonnade, called the 
Painted Stoa, renowned for its spectacular murals.  
In time, Zeno and his students became known as the 
men of the Stoa, or Stoics.  Here he taught a moral system 
based upon nature: the guide to human happiness, he 
said, is clearly evident in the processes and cycles of 
nature.  Upon these teachings the school was founded,
continuing through the Roman Stoa, the Christian Stoa, 
and into the present period."
[ Quoted with permission from Erik Wiegardt's CYBERSTOA.]