E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The matrimonial Matterhorn. The leap in the dark. The Matterhorn is the German name for Mont Cervin, a mountain of the Pennine Alps, about 40 miles east-north-east of Mont Blanc. Above an unbroken glacier-line of 11,000 feet high, it rises in an inaccessible obelisk of rock more than 3,000 feet higher. The total elevation of the Matterhorn is 14,836 feet. Figuratively any danger, or desperate situation threatening destruction.