Theatre Latté Da's "Steerage Song" is a musical documentary of the great wave of immigration that passed through Ellis Island in the late 19th and early 20th centuries. Heard Saturday night at the Lab Theatre in Minneapolis, the musical performance was exemplary.

Latté Da artistic director Peter Rothstein and musician and storyteller Dan Chouinard have been working on the piece for the past five years, including a concert performance at the Fitzgerald Theatre in 2011. They have transformed it since them, tightening it significantly, but it remains, at its heart, a historical pageant.

"Steerage Song" is made up entirely of found material. It's hard to imagine the amount of research that was done to find all the texts and music.

The texts, coming from books and newspaper articles of the period, are interwoven with the songs. They give a context for the music, but are too often dryly factual rather than emotional.

The first half covers the journey to America and the second half describes the experience here. The story of Irving Berlin's family's emigration gives the piece its strongest, most poignant emotional through line

The music is an amazing collection of Jewish folk songs and native songs from England, Ireland and Scotland, Italy and France, Poland and Hungary, Bulgaria and Slovenia, Finland and Norway, plus songs from Tin Pan Alley. They are sung in the original languages as well as in translation when necessary, increasing their storytelling power.

As music director, Chouinard arranges the songs evocatively for the strong five-piece ensemble. The singers are well-prepared, as demonstrated by the rich harmonies and the accuracy of the accents.

Rothstein demonstrates his skill as a director with a simple and uncomplicated staging. There are many simple moments, like a hand brushing a shoulder, that proved heart-rending.

The nine-member cast, a number of whom have been with the project from its inception, create a powerful ensemble, delivering strong, culturally authentic performances of the diverse repertoire. They rarely fail to deliver a strong, emotional impact.

The choice to end the piece with the 1924 establishment of national-racial quotas on immigration gives "Steerage Song" a timely, contemporary comment, and provides an emotional context to the current immigration debate.

William Randall Beard writes about music and theater.