One example of constitutionalism's descriptive use is law professor Bernard Schwartz's 5 volume compilation of sources seeking to trace the origins of the U.S. Bill of Rights. Beginning with English antecedents going back to Magna Carta (1215), Schwartz explores the presence and development of ideas of individual freedoms and privileges through colonial charters and legal understandings. Then, in carrying the story forward, he identifies revolutionary declarations and constitutions, documents and judicial decisions of the Confederation period and the formation of the federal Constitution. Finally, he turns to the debates over the federal Constitution's ratification that ultimately provided mounting pressure for a federal bill of rights. While hardly presenting a "straight-line," the account illustrates the historical struggle to recognize and enshrine constitutional rights and principles in a constitutional order.