Although views on what is appropriate in tax policy influence the choice and structure of tax codes, patterns of taxation throughout history can be explained largely by administrative considerations. For example, because imported products are easier to tax than domestic output, import duties were among the earliest taxes. Similarly, the simple turnover tax (levied on gross sales) long held sway before the invention of the economically superior but administratively more demanding VAT (which allows credit for tax paid on purchases). It is easier to identify, and thus tax, real property than other assets; and a head (poll) tax is even easier to implement. It is not surprising, therefore, that the first direct levies were head and land taxes.

Although taxation has a long history, it played a relatively minor role in the ancient world. Taxes on consumption were levied in Greece and Rome. Tariffs—taxes on imported goods—were often of considerably more importance than internal excises so far as the production of revenue went. As a means of raising additional funds in time of war, taxes on property would be temporarily imposed. For a long time these taxes were confined to real property, but later they were extended to other assets. Real estate transactions also were taxed. In Greece free citizens had different tax obligations from slaves, and the tax laws of the Roman Empire distinguished between nationals and residents of conquered territories.

Early Roman forms of taxation included consumption taxes, customs duties, and certain “direct” taxes. The principal of these was the tributum, paid by citizens and usually levied as a head tax; later, when additional revenue was required, the base of this tax was extended to real estate holdings. In the time of Julius Caesar, a 1 percent general sales tax was introduced (centesima rerum venalium). The provinces relied for their revenues on head taxes and land taxes; the latter consisted initially of fixed liabilities regardless of the return from the land, as in Persia and Egypt, but later the land tax was modified to achieve a certain correspondence with the fertility of the land, or, alternatively, a 10th of the produce was collected as a tax in kind (the tithe). It is noteworthy that at a relatively early time Rome had an inheritance tax of 5 percent, later 10 percent; however, close relatives of the deceased were exempted. For a long time tax collection was left to middlemen, or “tax farmers,” who contracted to collect the taxes for a share of the proceeds; under Caesar collection was delegated to civil servants.

In the Middle Ages many of these ancient taxes, especially the direct levies, gave way to a variety of obligatory services and a system of “aids” (most of which amounted to gifts). The main indirect taxes were transit duties (a charge on goods that pass through a particular country) and market fees. In the cities the concept developed of a tax obligation encompassing all residents: the burden of taxes on certain foods and beverages was intended to be borne partly by consumers and partly by producers and tradesmen. During the later Middle Ages some German and Italian cities introduced several direct taxes: head taxes for the poor and net-worth taxes or, occasionally, crude income taxes for the rich. (The income tax was administered through self-assessment and an oath taken before a civic commission.) Taxes on land and on houses gradually increased.

Taxes have been a major subject of political controversy throughout history, even before they constituted a sizable share of the national income. A famous instance is the rebellion of the American colonies against Great Britain, when the colonists refused to pay taxes imposed by a Parliament in which they had no voice—hence the slogan, “No taxation without representation.” Another instance is the French Revolution of 1789, in which the inequitable distribution of the tax burden was a major factor.

Wars have influenced taxes much more than taxes have influenced revolutions. Many taxes, notably the income tax (first introduced in Great Britain in 1799) and the turnover or purchase tax (Germany, 1918; Great Britain, 1940), began as “temporary” war measures. Similarly, the withholding method of income tax collection began as a wartime innovation in France, the United States, and Britain. World War II converted the income taxes of many countries from upper-class taxes to mass taxes.

It is hardly necessary to mention the role that tax policies play in peacetime politics, where the influence of powerful, well-organized pressure groups is great. Arguments for tax reform, particularly in the area of income taxes, are perennially at issue in the domestic politics of many countries.

The development of taxation in recent times can be summarized by the following general statements, although allowance must be made for considerable national differences: The authority of the sovereign to levy taxes in a more or less arbitrary fashion has been lost, and the power to tax now generally resides in parliamentary bodies. The level of most taxes has risen substantially and so has the ratio of tax revenues to the national income. Taxes today are collected in money, not in goods. Tax farming—the collection of taxes by outside contractors—has been abolished, and taxes are instead assessed and collected by civil servants. (On the other hand, as a means of overcoming the inefficiencies of government agencies, tax collection has recently been contracted to banks in many less-developed countries. In addition, some countries are outsourcing the administration of customs duties.)

There has also been a reduction in reliance on customs duties and excises. Many countries increasingly rely on sales taxes and other general consumption taxes. An important late 20th-century development was the replacement of turnover taxes with value-added taxes. Taxes on the privilege of doing business and on real property lost ground, although they have persisted as important revenue sources for local communities. The absolute and relative weight of direct personal taxation has been growing in most of the developed countries, and increasing attention has been focused on VAT and payroll taxes. At the end of the 20th century the expansion of e-commerce created serious challenges for the administration of VAT, income taxes, and sales taxes. The problems of tax administration were compounded by the anonymity of buyers and sellers, the possibility of conducting business from offshore tax havens, the fact that tax authorities cannot monitor the flow of digitized products or intellectual property, and the spate of untraceable money flows.

Income taxation (of individuals and of corporations), payroll taxes, general sales taxes, and (in some countries) property taxes bring in the greatest amounts of revenue in modern tax systems. The income tax has ceased to be a “rich man’s” tax; it is now paid by the general populace, and in several countries it is joined by a tax on net worth. The emphasis on the ability-to-pay principle and on the redistribution of wealth—which led to graduated rates and high top marginal income tax rates—appears to have peaked, having been replaced by greater concern for the economic distortions and disincentives caused by high tax rates. A good deal of fiscal centralization occurred through much of the 20th century, as reflected in the kinds of taxes levied by central governments. They now control the most important taxes (from a revenue-producing point of view): income and corporation taxes, payroll taxes, and value-added taxes. Yet, in the last decade of the 20th century, many countries experienced a greater decentralization of government and a consequent devolution of taxing powers to subnational governments. Proponents of decentralization argue that it can contribute to greater fiscal autonomy and responsibility, because it involves states and municipalities in the broader processes of tax policy; merely allowing lower-level governments to share in the tax revenues of central governments does not foster such autonomy.

Although it is difficult to make general distinctions between developed and less-developed countries, it is possible to detect some patterns in their relative reliance on various types of taxes. For example, developed countries usually rely more on individual income taxes and less on corporate income taxes than less-developed countries do. In developing countries, reliance on income taxes, especially on corporate income taxes, generally increases as the level of income rises. In addition, a relatively high percentage of the total tax revenue of industrialized countries comes from domestic consumption taxes, especially the value-added tax (rather than the simpler turnover tax). Social security taxes—commonly collected as payroll taxes—are much more important in developed countries and the more-affluent developing countries than in the poorest countries, reflecting the near lack of social security systems in the latter. Indeed, in many developed countries, payroll taxes rival or surpass the individual income tax as a source of revenue. Demographic trends and their consequences (in particular, the aging of the world’s working population and the need to finance public pensions) threaten to raise payroll taxes to increasingly steep levels. Some countries have responded by privatizing the provision of pensions—e.g., by substituting mandatory contributions to individual accounts for payroll taxes.

Taxes in general represent a much higher percentage of national output in developed countries than in developing countries. Similarly, more national output is channeled to governmental use through taxation in developing countries with the highest levels of income than in those with lesser incomes. Indeed, in many respects the tax systems of the developing countries with the highest levels of income have more in common with those of developed countries than they have with the tax systems of the poorest developing countries.