[4] On his first expedition in 1859, he joined U.S. explorer Frederick W. Lander, taking photographs of Native Americans[2] and painting field sketches of the landscape.

[11] Bierstadt desired to return to the West, "in search of a subject for a great Rocky Mountain picture",[12] so in April 1863,[13] he departed New York with his friend and explorer, Fitz Hugh Ludlow[13] and two other gentlemen.

[14] They met Ludlow's wife, Rosalie Osborne, in St. Louis, Missouri,[15] who accompanied them as far as Atchison, Kansas,[16] the starting point for the Overland Trail stagecoach.

The journey would not have been possible because they lacked suitable vehicles,[16] but Governor John Evans kindly lent the expedition his ambulance wagon and "a pair of stout serviceable" horses.

[27] Thirty miles into their journey, they arrived at Castle Rock, "a peculiar hill of the butte kind, a single cone, rising abrupt and solitary out of the level plain to the height of about four hundred feet".

[29] The expedition spent three days[30] at the base of Pike's Peak to explore the Fontaine qui Bouille (now called Fountain Creek), which allowed the men to bathe[31] before beginning their work, making studies and collecting samples of the local geology.

[34] The men enjoyed squeezing into a narrow cavern and reaching "a vault about fifty feet long, ten feet high", which they examined by candlelight, and comparing the Garden's rock formations to recognizable shapes, including animals and "a statue of Liberty, standing by her escutcheon, with the usual Phrygian cap on her head.

"[35] The men were so impressed by the landscape, that "[i]t was a great disappointment to some of our kind friends that our artist [Bierstadt] did not choose the Garden of the Gods for a 'big picture.'

Bierstadt separated from his expedition, and he and Byers rode a buckboard up to Idaho Springs,[12] located 30 miles west of Denver.

"[12] Despite the rainy weather, they headed south from Idaho Springs further into the mountains, with Byers in the lead and Bierstadt behind the pack animals.

Taking in the view for a moment, he slid off his mule, glanced quickly to see where the jack was that carried his paint outfit, walked sideways to it and began fumbling at the lash-ropes, all the time keeping his eyes on the scene up the valley.

The weather, however deteriorated, was impressive, and the view in front of Bierstadt included storm clouds drifting low over "sharp pinnacles and spires and masses of broken granite".

Rays of sunlight broke through the cloud, and flowing down a mountain were "ribbons of water from the last hard shower [ ... ] reflecting back the sunshine."

[43] William Henry Jackson would take a photograph of Lower Chicago Lake ten years later in nearly the same spot that Bierstadt painted his study.

[38][41][45] Bierstadt and Byers's return trip to Denver was "uneventful"[41] and Fitz Hugh Ludlow would get to look at Bierstadt's studies, which he later described as "some of the finest color studies he made along that [mountain] chain—among others an exquisite series of lakes on a mountain to whose very top he ascended with his color-box, a height of over 15,000 feet, or considerably taller than Mont Blanc.

"[16] Ludlow marveled at the landscape sketches and their colors and especially of the main peak[16] that Bierstadt had named: That glorious roseate mountain stood nameless among the peaks in its virgin vail of snew [sic, "veil of snow"]; so Bierstadt, by right of first portrayal, baptized it after one far away from our sides, but very near and dear to our hearts—a gentle nature who had followed us clear to the verge of our Overland wanderings at Atchison, and parted from us bravely lest she should make our purpose fainter by seeming moved.

[54] On 7 February 1866, A Storm in the Rocky Mountains, Mount Rosalie exhibited for one day and evening at the Somerville Art Gallery in New York City as a benefit for the "Nursery and Child's Hospital".