Now, what do we know about the original Vulcans?

Maybe the first Vulcans were the result of a colonization-programm of Sargon's people (see TOS:"Return to Tomorrow")

[...] It must be the Sarpeidon Ice Age, 5,000 years ago [...]
McCoy: Think, man. What's happening on your planet right now at this very moment?
Spock: "My ancestors are barbarians, warlike barbarians.
Who nearly killed themselves off with their own passions."

from TOS 3rd season: All Our Yesterdays, 2267

Therefore 2300 BC and before Vulcans were brutal Barbarians following their emotions.

Surak was at the begin of a new chapter in the Vulcan history:

Spock: Surak. - The greatest of all who ever lived on our planet, Captain. The father of all we became.
[...]
Surak: In my time on Vulcan, we also faced these same alternatives. We'd suffered devastating wars,
which nearly destroyed our planet. Another was about to begin. We were torn. But out of our suffering some of us found the discipline to act. We sent emissaries to our opponents to propose peace.
The first were killed, but others followed. Ultimately, we achieved peace, which has lasted since then.

from TOS 3rd season: The Savage Curtain

Spock: It [being a Vulcan] means to adopt a philosophy, a way of life which is logical and beneficial. We cannot disregard that philosophy merely for personal gain, no matter how important that gain might be.

from TOS: Journey to Babel

At this time the Romulans must have left Vulcan:

Spock: If Romulans are an offshoot of my Vulcan blood, then attack becomes even more imperative.
McCoy: War is never imperative.
Spock: It is for them, Doctor. Vulcan, like Earth, had its aggressive colonizing period, savage even by Earth standards. If Romulans retain this martial philosophy, then we dare not show weakness.

from TOS 1st season: Balance of Terror

The Romulans followed the way of the warrior-way of their anchestors, and left the planet because the emotionless philosophy.

"Spock: Where there's no emotion, there's no motive for violence."

from TOS Dagger of the Mind

Around c2160 the Romulan Star Empire was already established and in a war with Earth. Therefore Sarek, who was born 2163 or 2164 as "the child of Skon, child of Solkar" (see Star Trek III: The Search for Spock), was already a typical Vulcan following Suraks philosophy. But there are other hints about the begin of the logical Vulcans:

Spock: Mankind - ready to kill. That's the way it was in 1881. I wonder how humanity managed to survive? We overcame our instinct for violence.

That sounds, if the Vulcans left their violence behind already 1881!

Sarek

2229

Let's start with Spock:

Roddenberry 1976 in: "Inside Star Trek" - see also transcript by Dr. Maggie and published 8.3.2002

Sp

Vulcan, like earth, had it's aggressive colonizing period, savage even by Earth standards. Only the Discipline of logic saved there world.

about 150 years ago we had First contact with Vulcans. It was before Cochrane disappeared into deep space. Cochrane knew of the Vulcan's just not very well. this was Pre Federation.

Vulcan is a founding world of the United Federation of Planets ("Gambit, Part II" [TNG]) and due to its close promximity to Earth (15.9 light years) and similar history, is that planet's greatest political ally. Vulcan was the first extraterrestrial civilization to come in contact with Terran humans, on Earth, doing so on 5 April 2063 [Star Trek: First Contact].

Possibly descendants of humanoids who lived on Sargon's planet over 500,000 years ago ("Return to Tomorrow" [TOS]), Vulcan was a world of violent and incredibly passionate people until the philosophers Surak (c. AD 360s) and T'plana-Hath ("The Savage Curtain" [TOS]; Star Trek IV) led Vulcan to reject their overpowering emotions in favor of a philosophy of logical thinking in a period called the Time of Awakening ("Gambit, Part II" [TNG]).

Surak developed the philosophy of Knome, meaning All. he installed a sense of Logic into the Vulcan race.

On Vulcan Surak is considered the Father of their civilization. The Father image holds much meaning to the Vulcans. The Father of all Vulcan holds true.

"Surly it is more logical to heal, then Kill."
"May we together become greater then the sum of both of us"

T'Plana-Hath

Episode: MOV 004 - Star Trek IV: The Voyage Home
One of her most famous quotes is, "Logic is the cement of our civilization with which we ascend from chaos using reason as our guide."Considered the matron of Vulcan philosophy.

One of the founders of Vulcan philosophy. Her principle beginning, "Logic is the cement of our civilization..." was part of Spock's retraining in 2286.

Spock Learned his Earth History from Text prepared by John Gil. What impressed him most was his treatment of Earth History as cause and motivation's not date's and event's.

Vulcan is now noted for its total reliance upon logic and its famous rejection and supression of all emotional states, summed in their philosophy of Infinite Diversity in Infinite Combinations ("Is There in Truth no Beauty?" [TOS]) [note: one rebel Vulcan group rejected the logic philosophy and emigrated to several planets in the Romulan star system, forming the warrior Romulan Star Empire ("Unification, Part I" [TNG])].

sitar, daystrome.

see http://titulky.trekdnes.cz/titulky/tos-ep54.srt