Radical Traditionalist Catholicism

Is a centrism on the radical (root) Romish Catholic doctrines and customs, varying in how deep to the Root of the Tradition it goes. Some place most emphasis on the early centuries of the Romish Catholic Church, while others mostly emphasize on a period closer to the End of the Middle-Ages. The aforesaid Radicals (the word means properly those who seek ‘root’ interaction) are the deeper-going variant to the more Vanilla type commonly known as the briefer term: Traditionalist Catholicism which is a movement of Romish Catholics focusing on more recent periods (i.e. after the Middle-Ages), in any case, (and particularly in the most Vanilla Flavor, just right) before the Second Vatican Council (1962–65). 
The SPLC notes in a web page retrieved Apr 2018, that a few unnamed "adherents of Radical Traditional Catholicism, or ‘integrism’, routinely pillory Jews as the ‘perpetual enemy of Christ’ and worse," reject the ecumenical efforts of the Vatican, and sometimes even assert that recent popes have all been illegitimate. 
Gevolian Romish Traditionalism is a reading of Romish Catholicism through René Guénon, Julius Evola. It has been noted to differ from Vanilla Romish Catholicism in that it recognises e.g. Hyperborean Influence on Catholicism, and studies such influences through the Egyptian, Hebrew, Roman—and later, Germanic—influence on Early Christianity, e.g. as seen in the Christian Roman Empire, and from the Heathen Roman Empire. The web site Gornahoor, although varied in sources and treatments, has discoursed upon topics overlapping with Radical Traditionalist Catholicism, especially in relation to Guénon's and Evola's treatment of Catholic Tradition, and is estimated to be frequented by at least a couple such Traditionalists. 
[Wikip. r. 2018, notes] the vast majority of traditional Catholics regard the newer rites of the sacraments and the post-Vatican II popes as valid, and attend traditional Masses offered by diocesan priests, the Institute of Christ the King Sovereign Priest (ICKSP), FSSP, or SSPX. ... The traditionalist movement traces its roots to at least the early 1970s, where conservative Catholics opposed to or uncomfortable with the social and liturgical changes brought about by Second Vatican Council began to coalesce. In 1970, French Archbishop Marcel Lefebvre founded the Society of Saint Pius X (SSPX), made up of priests who would say only the Traditional Latin Mass and who stood opposed to what he saw as excessive liberal influences in the Church.The Society of St. Pius X (SSPX) is a fervently traditionalist Catholic sect: a Vatican breakaway with no official Church status, and the cause of much malcontent in Rome. Born in reaction to the Church’s modernizing reforms of the ’60s, the Society soon emerged as a stronghold of the way Catholicism used to be. In the towns and cities where SSPX communities popped up (SSPX claims almost half a million members, hundreds of priests, and a presence on every continent, though the numbers cannot be verified), the group is best known for its practice of the old Tridentine Mass: conducted in Latin, the priest’s back to his congregation, and heavy on the Gregorian chant. [Salon.com, Nov, 2013]See also: Cafeteria Catholic; Counter-Reformation; Extra Ecclesiam nulla salus; Second Vatican Council; Mass of Paul VI; Sedevacantism; Tridentine Mass; Catholic fundamentalism
See also: Germanic Influence on Early Romish Catholicism.