I second Pilgrim Church as one great definite resource, also the Foxes Book of Martyrs has a section on them:
Though its from Ellen G. White founder of Seventh Day Aventism which is full of doctrinal errors here is a good article by her on this group except for some claims that they kept the saturday sabbath etc:
a good explanation of this is here from a Waldenese minister:
June 21, 2006
Dear Brother Andras,
My name is Thomas Soggin, a Waldensian Minister in Bergamo (North Italy), in charge - by our Board, the Tavola Valdese - to answer to your letter.
If you are interested in the Waldensian Churches in Italy (North, Center, and South Italy) and in Uruguay and Argentina, in past and present you can look in the site of our Publishing House: Claudiana (Torino), and email. You can try also to find and study the following book: Giorgio Tourn, You are my witnesses The Waldensians across 800 years, Claudiana Editor 1989 - Distributed in North America by P.O. Box 37844 - CINCINNATI,OH 45222 (USA).
In their 350 years before the Reformation their real problem was baptism - the link between baptism and Roman Catholic constantinianism, not the problem of baptism (by immersion or with sprinkling), neither the problem of Sabbath instead of Sunday.
In a well-supplied library you can try to find the following books:
1) Jean Gonnet - Amedeo Molnar, Les vaudois au moyen age, Claudiana, Torino 1974 (French): In the XV century all the Waldensians (France, Italy: Piedmont, Calabria) where united with the Hussite movement: the Taborites Czechs (c/o Jan Hus! In that time there are also some Waldensians documents on baptism: pp., 434-437).
2) Amedeo Molnar, Storia dei valdesi/1, Dalle origini alladesione alla Riforma, Claudiana, Torino 1974 (Italian). (They did not have interest in baptism as St. Paul wrote in I Cor.1,17): p. 274).
3) Carlo Papini, Valdo di Lione e i «poveri nello spirito», Claudiana, Torino, 2001.
They were called: Mater Reformationis (=Mother of the Reformation) when they were before, as you know, during the Middle Ages a movement, but NOT a Church. After the Synod of Chanforan in Angrogne (1532) and later on, the Waldensians become a Reformed Presbyterian Church, as in Geneva. They adopted the Huguenot Reformed Confession of faith, of the so called Synod De la Rochelle of 1559 (but it was really the Paris Synod, their first Huguenot General Assembly).
But in 1655 the Waldensian Churches had its own Confession of Faith, hurriedly drafted in Italian immediately after the massacre of the Waldenses, called Piedmonts Easters (See Miltons Avange o Lord
!. This confession of faith was simply a shortened version in Italian of the Huguenot Confession of faith of 1559: it confirmed that theologycally the Waldenses were in the mainstream of Presbyterian Calvinism. It is still the basis of nowadays Waldensian beliefs, which the Candidates have to undersign in front of the General Assembly before becoming ordained as Ministers (VDM) in our churches (without any kind of Anabaptism, or Sabbath instead of Sunday!).
Therefore, the Waldensians did not keep the Sabbath (in the sense of Saturday instead of Sunday) and were not guardians of the "Sabbath Truth as somebody calls it. The Waldensians never followed the Seventh-day Adventists Sabbath but they followed more Paul in Romans 14,5-8.
We can therefore say very clearly that the Waldensians were not Seventh-day Sabbath keepers and they were not persecuted for keeping Saturday as the Sabbath! Thy were persecuted, [from 1532 (when they joined the Reformation - Angrogna Synod) to 1848 (when they received religious freedom)], because of their Reformed-Calvinistic faith in Christ.
With my best regards, yours, Thomas Soggin
SI Moderator - Greg Gordon