“Leon Botstein, an indispensable advocate of the unfairly ignored, brought his ensemble The Orchestra Now to Carnegie Hall on Thursday for an evening of works that, despite covering a range of nearly 150 years, felt as fresh as a batch of premieres.

Botstein belongs to a class of conductors and artistic directors — including historian Joseph Horowitz, as well as Gil Rose of the Boston Modern Orchestra Project, Ashleigh Gordon and Anthony R. Green of Castle of Our Skins, and more — who bring an endlessly curious and almost archaeological mind to their programming. They operate on such a small scale, they can hardly reverse the course of American classical music history; but each concert, each recording, is an essential step in a better direction.

On Thursday, Botstein and The Orchestra Now, a capable and game group of young musicians, took the latest of those steps with Julia Perry’s Stabat Mater, written in 1951, early in that composer’s short life; Scott Wheeler’s new violin concerto, Birds of America, featuring Gil Shaham; and George Frederick Bristow’s Fourth Symphony, Arcadian, from 1872.

The mezzo-soprano Briana Hunter navigated her part’s surprising turns and plunges in Perry’s Stabat Mater with smooth and characterful ease. . . . Shaham, one of our sunniest violinists, entered Wheeler’s concerto with a singing melody on his highest string, and brought abundant warmth throughout. But he was also grippingly virtuosic in tricky, Sarasate-like passages of lyrical double-stops and left-hand pizzicato. ” –Joshua Barone