Nathaniel Bacon gained the approval of the Virginia Assembly for his expedition by appealing to the colonists' grievances against the colonial government and the Native American tribes. In 1676, Bacon and his followers felt that the colonial government was not doing enough to protect the settlers from attacks by Native Americans.
Bacon presented a petition to Governor William Berkeley requesting permission to raise a militia to fight against the Native Americans. However, Berkeley refused to grant Bacon the authority to do so. Bacon and his supporters then took matters into their own hands and organized a rebellion against the colonial government.
Bacon was able to gain the support of the Virginia Assembly by arguing that the colonial government was not protecting the settlers and that a militia was necessary to defend against Native American attacks. The Assembly ultimately agreed to allow Bacon to lead an expedition against the Native Americans.
Bacon's expedition was successful in driving back the Native American tribes and in establishing himself as a leader in Virginia. However, his rebellion ultimately failed, and he died of dysentery before it was fully resolved.