I Lombardi alla Prima Crociata (The Lombards on the First Crusade) is an operatic dramma lirico in four acts by Giuseppe Verdi to an Italian libretto by Temistocle Solera, based on an epic poem by Tommaso Grossi, which was "very much a child of its age; a grand historical novel with a patriotic slant". Its first performance was given at the Teatro alla Scala in Milan on 11 February 1843. Verdi dedicated the score to Maria Luigia, the Habsburg Duchess of Parma, who died a few weeks after the premiere.

In 1847, the opera was significantly revised to become Verdi's first grand opera for performances in French at the Salle Le Peletier of the Paris Opera under the title of Jérusalem.

The plot complications of Tasso's original drama required the librettist to make significant changes; the historical characters portrayed in the original do not appear and the story becomes that of a fictional family and its involvement in the Crusades. Julian Budden's analysis of the opera's origins notes: "In 1843 any subject where Italian were shown united against a common enemy was dangerous, especially in Austrian Milan. Yet strangely enough it was not the police but the church that took exception to I Lombardi", since the Archbishop of Milan had heard rumours that the work contained specific elements of Catholic ritual. However, given Verdi's refusal to make any changes to the music, it is fortunate that the result of the police chief's investigations of the archbishops complaints required only very minor alterations.