Peter Waldo, Valdo, or Waldes (c. 1140 – c. 1218), also Pierre Vaudès or de Vaux, was the founder of the Waldensians, a Christian spiritual movement of the Middle Ages, descendants of which still exist in various regions.
Waldo also began to preach and teach on the streets, based on his ideas of simplicity and poverty, notably that "No man can serve two masters, God and mammon." By 1170 he had gathered a number of followers and they started to be called the Poor of Lyon, the Poor of Lombardy, or the Poor of God. They were also referred to as the Waldensians (or Waldenses), after their leader. They were distinct from the Albigensians or Cathars.
The Waldensian movement was characterised from the beginning by lay preaching, voluntary poverty and sticking to the "Word of God", the Bible. Peter Waldo commissioned a cleric from Lyons around 1180 to translate the Bible, or parts of it, into vernacular, the provençal language.
In 1179, Waldo and one of his disciples went to Rome. They were welcomed by Pope Alexander III, and by the Roman Curia. They had to explain their faith before a panel of three clergymen, including items which were then debated within the Church, as the universal priesthood, the gospel in the vulgar tongue, and the issue of self-imposed poverty. But Waldo and his friend were not taken seriously. The meeting therefore resolved nothing, and Waldo’s and his followers’ ideas, initially regarded with suspicion, were condemned at the Third Lateran Council in the same year, but the leaders of the movement had not been yet excommunicated.
Driven away from Lyon, Waldo and his followers settled in the high valleys of Piedmont, and in France, in the Luberon. Finally, Waldo was excommunicated by Pope Lucius III during the synod held at Verona in 1184, and the doctrine of the Poor of Lyon was again condemned by the Fourth Lateran Council in 1215, and regarded as heresy. The Roman church began to persecute the Waldensians, and many were tried and sentenced to death in various European countries during the 12th, 13th, and 14th centuries. Centuries after his death, the Waldensian denomination joined the Genevan or Reformed branch of the Protestant Reformation.