Basel became the focal point of western Christendom during the 15th century Council of Basel (1431–1449), including the 1439 election of antipope Felix V. In 1459 Pope Pius II endowed the University of Basel where such notables as Erasmus of Rotterdam and Paracelsus later taught. Following the Imperial Reform of 1495, the prince-bishopric was part of the Upper Rhenish Circle of the Imperial Circle Estates.