Rationalism and empiricism have had many definitions, most concerned with specific schools of philosophy or groups of philosophers in particular countries, such as Germany. In general rationalism is the predominant school of thought in the multi-national, cross-cultural Age of reason, which began in the century straddling 1600 as a conventional date, empiricism is the reliance on sensory data gathered in experimentation by scientists of any country, who, in the Age of Reason were rationalists. An early professed empiricist, Thomas Hobbes, known as an eccentric denizen of the court of Charles II of England (an "old bear"), published in 1651 "Leviathan", a political treatise written during the English Civil War, containing an early manifesto in English of rationalism.