How did feudal land rules contribute to the development of inheritance taxes in Europe?

The modern inheritance tax is rooted in the feudal system of the Middle Ages, during which all land and property were considered to be ultimately owned by the sovereign.1

Because the monarch held ultimate ownership, their permission was required to transfer property upon the death of a vassal. If a deceased vassal had no direct descendants, their relatives were required to pay a fee known as a "relief" to the overlord to obtain the right to inherit the property.12

These relief payments, which eventually became standardized—often at the equivalent of one year’s revenue from the fief—served as a precursor to modern succession duties. In many European nations, including Great Britain, Spain, Portugal, and the Netherlands, current inheritance tax systems can be traced directly back to these feudal practices.12