From the pharaohs of ancient Egypt through the monarchies of Europe and Asia Minor to modern democratic representative governments, taxes on property have been a central form of revenue. Property taxes are called "ad valorem," from the Latin meaning "from the value." In order to determine the amount of property tax, the first step is appraise the value of the property to be taxed. In early times, only tangible property, such as land, houses, and cattle were valued. The people who did this valuation were originally the tax collectors, who set the values and collected the taxes, sometimes right on the spot under threat of bodily harm or death.

In more modern societies, the functions are usually split between the appraisal function, also know as the assessment function, hence Assessor, and the calculation and collection functions. Threats of bodily harm and direct seizure have been replaced by tax liens, tax-deeded auctions and other more humane, but no less effective, measures. In California, the Constitution says that all property is taxable, but in the second half of the 19th century, the legislature exempted intangible property such as bank accounts, stocks and bonds from taxation. Since then, household furnishings, most livestock and business inventory have been removed from the tax rolls.