There had been numerous conflicts between the Vestians and the Federation in the early years of the 23rd century. A treaty between the two in the 2240s ensured peace between the two for several years.
In 2246, a civil war broke out amongst the Vestians, involving rebels on Vestios II. These rebels attacked Federation ships, apparently in an effort to involve the Federation in the fighting. Toward the end of the war, a Starfleet ship patroling the border, the USS Aldrin, did destroy a rebel ship, and fired on an official military vessel. When Lieutenant Commander Christopher Pike relieved Captain Kamnach of his command, the Vestians opted to overlook these instances to avoid an interstellar incident.