Wikipedia
Neo-ultramontanism (or new ultramontanism) is the belief of certain Roman Catholics, primarily during the period immediately prior to Vatican I, that papal infallibility was not restricted to a small number of papal statements but applied ipso facto (by virtue of being said by the Pope) to all papal teachings and statements.
Although few of today's Catholic Church historians distinguish between neo-ultramontanism and the more moderate ultramontanism of mainstream nineteenth-century Catholicism, there were substantial differences between the two. The neo-ultramontanes wanted to pass by decree the most extreme definition of papal infallibility possible and did not wish for debates at all. They were, indeed, regarded as imprudent by more moderate ultramontanists who won the debate at Vatican I.