Johannes Althusius was a German political theorist born in 1557, known for his contributions to the development of federalism. He is best recognized for his work, Politica, published in 1603, where he outlined his ideas on the relationship between individuals, communities, and the state. Althusius emphasized the importance of social contracts and the role of civil society in governance. Althusius's theories influenced later thinkers, including John Locke and Jean-Jacques Rousseau, and laid the groundwork for modern concepts of democracy and federalism. His ideas highlighted the significance of voluntary associations and the balance of power within a political system.