Vulcan-Andorian history is marked with great tensions between the powers of Vulcan and the Andorian Empire in the 22nd century.
First Contact and Beginning of Hostilities
At first, relations between Vulcan and Andor were promising, but the Vulcans believed that the Andorians were duplicitous, wishing to only honor agreements that did not conflict with their interests. In the 1950s, the Vulcans were suspicious of the Andorians' territorial and militaristic nature while the Andorians believed that the only thing keeping the Vulcans from invasion was the threat of mass retaliation. The class D planetoid, called Weytahn by the Andorians and Paan Mokar by the Vulcans, was terraformed and colonized by the Andorians and had a key strategic position on the frontier between Vulcan and Andoria. After the Andorians refused to allow the Vulcans to inspect the colony for an invasion force, the Vulcan High Command ordered the forced removal of all Andorian colonists. (ENT: "Cease Fire")
Cold War
The Vulcans and Andorians signed a peace treaty and the Vulcans put a satellite in orbit of Paan Mokar to see that the treaty was obeyed. The Vulcans also created a very powerful surveillance device under the ancient monastery of P'Jem. The Andorians believed in strongly in the existence of the listening device and occupied the monastery several times but leaving soon after wards, not being able to prove in its existence until they were assisted by the Humans of the starship Enterprise. They later returned and bombed the monastery though they gave the monks a chance to escape. (ENT: "The Andorian Incident")
Another conflict in the cold war was when Coridan, an inhabited planet rich in dilithium that was controlled by a corrupt government supported by the Vulcan High Command, was undergoing a civil war where the rebels were being supported by the Andorians. (ENT: "Shadows of P'Jem")
Soon afterward, an old conflict re-emerged, the Vulcan satellite detected the Andorians landing on Paan Mokar and occupied the settlement. The Vulcans retaliated and took control of half of the settlement. The Vulcans then offered a cease fire which Shran, the commander of the Andorian regiment agreed to as long as Captain Jonathan Archer of the Earth starship Enterprise mediate the negotiations. The Vulcans and Andorians had reinforcements on the way, but with some help from the Humans they arranged a new fairer treaty. (ENT: "Cease Fire")
The Andorians assisted the Humans during the Enterprise's mission in the Delphic Expanse when they planned to steal the superweapon prototype, but the Andorians really planned to steal the weapon for themselves to gain the advantage in the Cold War, but it was destroyed by the Enterprise. (ENT: "Proving Ground")
Battle of Andoria and End of Cold War
Minister V'Las of the High Command, which had taken control of the Vulcan government, convinced the other ministers that the Andorians had recovered the Xindi technology. He used this fake evidence to convince the others that the best course of action was an invasion of Andoria. The Vulcans created fake warp signatures outside of Weytahn while a real fleet of twelve ships were amassed at Regulus, a star outside of the range of Andorian listening posts. The Andorians were only able to muster six ships and were aided by the Enterprise. After finding no Xindi technology on the Andorian ships, minister V'Las was overthrown (though the battle itself continued for sometime, see Battle of Andoria) and a new more peaceful government was installed on Vulcan thereby ending the Vulcan-Andorian Cold war. (ENT: "Kir'Shara")