Before the founding of the United States, colonial powers such as Britain, France and the Netherlands made land grants to favored individuals in the original colonies that evolved into large agricultural estates that resembled the manors familiar to Europeans. In fact, founding fathers such as George Washington, Thomas Jefferson and James Madison were the owners of large agricultural estates granted by colonial rulers and built large manor houses from which these estates were managed (e.g., Mount Vernon, Monticello). However, there were important distinctions. American agricultural estates often relied on slaves rather than tenant farmers or serfs which were common in Europe at the time. The owners of American agricultural estates did not have noble titles and there was no legally recognized political structure based on an aristocratic, land-owning class. As a result, this limited the development of a feudal or manorial land-owning system to just a few regions such as Tidewater and Piedmont Virginia, the Carolina Low Country, the Mississippi Delta, and the Hudson River Valley in the early years of the republic. Southern California (under Spanish and Mexican administration) also developed a primitive manorial society. However, even these exceptions did not produce European-style manorial social, political and economic structures and with a few notable exceptions, did not result in the extravagant manor houses as found throughout Europe.