Felix Mendelssohn was seasick. The composer, during his visit to the isle of Staffa in the Inner Hebrides on August 8, 1829, was “under the weather,” so to speak, on the steamer Ben Lomond. Unusually, he made no recorded reference later, in his letters or sketchbook, to the island's renowned Fingal's Cave, only to “the most fearful sickness” on the voyage. However, his companion, Karl Klingemann, cheerfully unaffected by the Hebridean swell, did provide a vivid description of the island and the cave, likening the pillars of the latter to “the inside of an immense organ, black and resounding, absolutely without purpose, and utterly isolated, the wide grey sea within and without.” The day before Mendelssohn's visit to Staffa, the composer had written to his family in Berlin, “In order to make you realize how extraordinarily the Hebrides have affected me, the following came into my mind there,” and followed this with a twenty-one-bar outline of the opening of his Die Hebriden (the “Hebrides” overture, op. 26, also titled “Overture to the Isles of Fingal” and “Fingal's Cave”) in short score.

Vividly, the orchestration of the piece evokes the Ossianic seascape by means of unusual melodic and harmonic devices as well as clarity of instrumental color; these together create a memorable procession of dovetailed tonal frescoes, the opening theme in B minor and its many repetitions capturing the swell of the sea and salty air, while later in the work trumpets recall the ghostly clamor of ancient battles as they unfold in the poems.

The experience must have unnerved the young composer, brought up as he had been in a cultivated, bourgeois environment in Berlin. That he made no record or account of his floating visit other than the overture itself is highly significant.