I did a Goggle and came up with the following.

George Martin

History of the Commissioner of the Revenue:
In 17th c. Virginia, tax assessment was initially the responsibility of the Governor and his Privy Council. This worked well until the growth of the colony forced change. The Governor appointed a sheriff for each sire. Among the duties of the sheriff was tax assessment. In the mid 1600’s, the responsibility for tax assessments was transferred from the sheriffs to the county courts, which was often delegated to special appointees by the court justices. However, during the Revolutionary War, the need for increased taxes placed an extreme burden on the system of having court justices make assessments, and as a result, the General Assembly provided for commissioners of tax.
After experimenting with various assessment procedures under the Commissioner of Tax, the General Assembly created Commissioners of Revenue in 1786. As the number of individuals and items subject to taxation rose, the importance of the commissioner’s task grew. Consequently, they acquired constitutional stature in 1851.
The Commissioner of the Revenue holds office as an agent for the state, as well as the local government, and is the assessing officer on the local level for those taxes prescribed by the state law and local ordinance. As such, the office serves as a bridge between the local level of government and the state legislature.
The office administers all taxes and programs as provided for in the Code of Virginia and is directly accountable to the citizens.
[http://www.co.caroline.va.us/commissioner.html]