Question: In what year did Jim Savage lead the Mariposa Battalion west?
About the article "Yosemite National Park", section "Ahwahneechee and the Mariposa Wars".

Candidate passages:
Jim Savage or James D. Savage, (1817–1852) was a California pioneer.
He was a 49er, businessman, American soldier in the Mexican American War, and commander of the California Militia, Mariposa Battalion in the Mariposa War, and the discoverer of the Yosemite Valley. 
When local militia failed to quell the uprising of the tribes, the governor of California, John McDougall put Savage at the head of a unit of State Militia called the Mariposa Battalion with the rank of Major.
On March 25, 1851, Savage marched at the head of a company of the Mariposa Battalion which included a Doctor Lafayette Bunnell, who wrote about the expedition.
Marching into the Sierra wilderness, they came upon Yosemite Valley at Inspiration Point and became the first non-indigenous discoverers of Yosemite Valley.
Discovery was not the main purpose of the trip: the Battalion rode out in search of Native American tribal leaders believed to have been involved in recent raids on American settlements.
After campaigns up the rivers into the mountains and taking control of the Yosemite, the tribes submitted to moving to a reservation ending the Mariposa War and the Mariposa Battalion was disbanded. 
Mariposa Battalion was a California State Militia unit formed in 1851 to fight the Yosemites and Chowchillas in the Mariposa War.
After a force under Mariposa County Sheriff James Burney was found unequal to the task of defeating the Indians, Burney made an appeal to Governor John McDougal for help.
This led to authorizing an organization of two hundred men into the Mariposa Battalion.
The Mariposa Battalion was mustered 12 February 1851.
Sheriff Burney was the first choice for the Major to command the unit, but Burney declined due to his other responsibilities in Mariposa.
James D. Savage was then chosen as major, primarily due to his scouting abilities.
The battalion was divided into three companies: Company A commanded by John J. Kuykendall, with seventy men; Company B under John Boling, with seventy-two men; and Company C, under William Dill, with fifty-five men.
Other officers elected included M. B. Lewis as Adjutant, A. Brunson as Surgeon and Vincent Hailor as Guide.
A camp was established two and one-half miles from the town of Mariposa near Savage's Agua Fria trading post. 
The first non-natives to see Yosemite Valley were probably members of the 1833 Joseph Walker Party, which was the first to cross the Sierra Nevada from east to west.
The first descriptions of Yosemite, however, came nearly 20 years later.
The 1849 California Gold Rush led to conflicts between miners and natives, and the state formed the volunteer Mariposa Battalion as a punitive expedition against natives in the Yosemite area.
In 1851, the Battalion was led by Major James D. Savage, whose trading post on the Merced River the Awaneechee had raided.
This and other missions resulted in Chief Teneiya and the Awaneechee spending months on a reservation in the San Joaquin Valley.
The band returned the next year to the Valley, but took refuge among the Mono Paiutes after further conflicts with miners.
Most of the Awaneechee (along with Teneiya) were chased back to the Valley and killed by the Paiutes after violating hospitality by stealing horses.
While the members of that first expedition of the Mariposa Battalion had heard rumours of what could be found up the Merced River, none were prepared for what they saw March 27, 1851 from what is now called Old Inspiration Point (close to the better visited Tunnel View).
Dr. Lafayette Bunnell later wrote:Camping that night on the Valley floor, the group agreed with the suggestion of Dr. Bunnell to call it "Yo-sem-i-ty", mistakenly believing that was the native name.
Bunnell was also the first of many to underestimate the height of the Valley walls.
A San Francisco newspaper demanded that he cut his estimate of the rim height—at 1500 feet (450 m), already under by half—in half again before they would publish it.
James Hutchings—who organized the first tourist party to the Valley in 1855—and artist Thomas Ayers generated much of the earliest publicity about Yosemite, creating articles and entire magazine issues about the Valley.
Ayres' highly detailed angularly exaggerated artwork and his written accounts were distributed nationally and an art exhibition of his drawings was held in New York City.
Two of Hutchings' first group of tourists, Milton and Houston Mann, built the first toll route into the valley, with development of the first hotels in the area and other trails quickly following.
Orchards were planted and livestock grazed in Valley meadows, with damage to native ecosystems as the result. 
The Mariposa War (December 1850 - June 1851) was a conflict between Native Americans and miners in what was then the immense county of Mariposa in California.