Peter Waldo, Valdo, or Waldes (c. 1140 - c. 1218), also Pierre Vaudès or de Vaux, is credited as the founder of the Waldensians, a Christianspiritual movement of the Middle_Ages, descendants of which still exist in various regions of southern Europe. Due to lack of reliable documentation there is a great degree of debate over Waldo's role in the Waldensian sect which may have existed before his leadership.
(copied and pasted from Wikipedia)
C. H. Strong has written: 'A brief sketch of the Waldenses' -- subject(s): Waldenses, History
Word of mouth
Nicholas Stoltzfus has written: 'Worth dying for' -- subject(s): Fiction, Waldenses
Pius Melia has written: 'The Origin, Persecutions And Doctrines Of The Waldenses' -- subject(s): History, Sources
Giovanni Gonnet has written: 'Il grano e le zizzanie' -- subject(s): Church history, History, Waldenses
Graziella Bonansea has written: 'Vite discrete' -- subject(s): History, Religious life and customs, Waldenses, Protestatnt women
Roger Geymonat has written: 'El templo y la escuela' -- subject(s): Emigration and immigration, Waldenses, History, Church history
Andrea Sossi has written: 'Medioevo valdese, 1173-1315' -- subject(s): Doctrines, Lord's Supper, Poverty, Preaching, Waldenses, History, Christianity
Balthasar Lydius has written: 'Waldensia, id est, Conservatio verae ecclesiae' -- subject(s): Early works to 1800, Taborites, Waldenses, Protestantism, History
Enrico Lantelme has written: 'I canti delle valli valdesi' -- subject- s -: Folk music, French Folk songs, History and criticism, Music, Waldenses
There are varying opinions on this and the evidence for Sabbath observance is a bit on the sketchy side, but a case could probably be made either way.
Emilio Comba has written: 'Storia della Riforma in Italia' 'I nostri Protestanti' 'Waldo and the Waldensians Before the Reformation' 'Storia de' Valdesi' -- subject(s): Waldenses