A more thorough explanation:

The doctrine of tenures is a historical rule that states that all land is held by the Crown, either directly or indirectly, on some type of tenure. This rule helps to determine the manner in which an estate is held.

For example, in medieval England, land was often held by feudal lords who owed allegiance to the king. The feudal lord would grant land to a tenant in exchange for services or rent. This created a system of hierarchical relationships between the king, the feudal lords, and the tenants.

Another example is the modern system of land ownership in the United States. Land is held by individuals or corporations, but the government retains certain rights, such as the power of eminent domain.

The doctrine of tenures is important because it establishes the relationship between the Crown and the landowner. It also helps to determine the rights and responsibilities of the landowner, such as the right to sell or lease the land.