The painting dates from the artist’s late period of landscape painting and can be regarded as contemporary with two paintings shown in Venice at the 10th Esposizione Internazionale d’Arte della Città di Venezia in 1912, namely Eclogue (whereabouts unknown, previously in the collection of the House of Savoy) and Dawn in the High Mountains (wherebouts unknown, formerly owned by Achille Aliprandi in Milan). The small lake depicted is in all probability one of the two at the foot of Pizzo Teo, a peak visible from the path leading from the Bernina range through the Upper Engadina valley. It was in this area that Longoni produced a number of paintings during the early years of the 20th century as well as preparatory sketches for the canvas entitled Dawn (private collection, exhibited at the Venice Biennale of 1905). In Spring in the High Mountains, like other works of the same period, the painter develops impressions captured from life a few years earlier, during long hikes among the Alpine peaks, to create new effects of light and colour. These are rendered by means of the Divisionist technique initially experimented with at the end of the 19th century and developed to obtain an effect of ever-greater evanescence in this period and later years. The quick, separate brushstrokes show the meadow in the thaw, already covered in rhododendrons, around the blue expanse of the still frozen lake. The background is painted with greater lightness to create an impalpable atmosphere and the Pizzo Teo is captured in pink and violet brushstrokes. While the flock of sheep driven by two figures glimpsed in the foreground can be seen as a sign of life alluding to the imminent spring, the small size of the group increases the sense of distance between the viewer and this mountain landscape, thus heightening its evocative power.