The public trust doctrine is the principle that the sovereign holds in trust for public use some resources such as shoreline between the high and low tide lines, regardless of private property ownership. Origins Justinian The ancient laws of the Byzantine Emperor Justinian held that the sea, the shores of the sea, the air and running water were common to everyone. The seashore, later defined as waters affected by the ebb and flow of the tides could not be appropriated for private use and was open to all. England This principle became the law in England as well. Centuries later, Magna Carta further strengthened public rights. At the insistence of English nobles, fishing weirs which obstructed free navigation were to be removed from rivers. United States These rights were further strengthened by later laws in England and subsequently became part of the common law of the United States. The Supreme Court first accepted the public trust doctrine in Martin v. Waddell’s Lessee in 1842, confirming it several decades later in Illinois Central Railroad v. Illinois, 146 U.S. 387 (1892). In the latter case the Illinois Legislature had granted an enormous portion of the Chicago harbor to the Illinois Central Railroad. A subsequent legislature sought to revoke the grant, claiming that original grant should not have been permitted in the first place. The court held that common law public trust doctrine prevented the government from alienating the public right to the lands under navigable waters (except in the case of very small portions of land which would have no effect on free access or navigation). The public trust applies to both waters influenced by the tides and waters that are navigable in fact. The public trust also applies to the natural resources (mineral or animal) contained in the soil and water over those public trust lands. Application This doctrine has been primarily significant in two areas: land access and use, and natural resource law. Access to ocean and ponds The doctrine is most often invoked in connection with access to the seashore. In the United States, the law differs among the fifty states but in general limits the rights of ocean-front property owners to exclude the public below the mean high tide line. Massachusetts and Maine (which share a common legal heritage) recognize private property ownership to the mean low tide line—but allow public access to the seashore between the low