As Broomfield-based Vail Resorts swallowed up the ski industry over the past decade, both domestically and abroad, mountain purists seemed resigned to the fact that eventually their favorite spots would be taken over by the corporate behemoth.

And who could blame them? In a four-year span Vail acquired—and merged—Park City Mountain Resort and the Canyons Resort to create the largest ski resort in the U.S.; bought Perisher, the largest mountain in Australia for $135 million; and if that weren’t enough, also vacuumed up Whistler Blackcomb, the most trafficked ski area in North America, for a cool $1.1 billion. By the beginning of 2017, six of the 10 most popular ski resorts in the United States were under the Vail umbrella, in addition to the aforementioned Whistler. And that was all before Vail purchased local-favorite Crested Butte.

Twenty miles away, though, executives from Denver-based KSL Capital Partners and Henry Crown Company (which owns Aspen Skiing Co.) were hammering out the details of a partnership that would send a message to Vail and the rest of the ski industry. That agreement, which would later form Alterra Mountain Company, was a shot across the bow of Vail Resorts, longtime rivals of Henry Crown affiliate Aspen Skiing Company. The message: Vail wasn’t the only game in town.

(Read More: A Complete List of Every Mountain Vail Resorts Has Ever Purchased)

Alterra has moved swiftly and decisively over the past 24 months to compete with Vail, making a point to snatch up some of the country’s most popular resorts and introducing the Ikon Pass, a similarly priced competitor to Vail’s Epic Pass. For riders, it essentially creates a duopoly in the American ski industry, though Alterra has been reticent to remind people of a key difference between the two: management. Unlike Vail, Alterra insists that it hasn’t—and won’t—alter its properties to match a corporate identity, instead allowing them to operate similar to how they had before the ownership change.

Last week, Alterra added more resorts to its repertoire, buying Vermont’s Sugarbush Resort to up its total to 15 properties, with limited access to 26 additional partner mountains worldwide. Here, we compiled a timeline of Alterra’s acquisitions and subsequent entrance into the fight to be North America’s premier resort conglomerate.

April 10, 2017
Henry Crown and Company and KSL Partners jointly acquire Intrawest Resorts for $1.5 billion, giving the duo ownership of not only Steamboat and Winter Park resorts, but also Quebec’s Tremblant, Ontario’s Blue Mountain, West Virginia’s Snowshoe, Vermont’s Stratton and Canadian Mountain Holidays, the world’s largest heliskiing outfit.

April 12, 2017
On the heels of acquiring Intrawest, the yet-to-be-named partnership buys California’s Big Bear, Mammoth Mountain, June Mountain, and Snow Summit two days later. Now with Steamboat, Winter Park, and Mammoth in its arsenal, the partnership owns three of the six most popular ski areas in the country. Copper Mountain, the only top-10 resort not owned by Alterra or Vail Resorts, was sold by Intrawest amid growing company debt a decade earlier and is now owned by Utah-based Powdr Corporation.

August 21, 2017

The KSL-HCC partnership makes its next major acquisition when it buys Deer Valley in Utah, known for its upscale amenities and ranked the best ski resort in the United States from 2013–17 by the World Ski Awards.

January 15, 2018
The KSL-HCC partnership finally gets a name: Alterra Mountain Company. The recently acquired Intrawest assets are merged with Squaw Valley and Alpine Meadows Ski Resort, which KSL purchased in 2010, to give the newly named Alterra one of the premier ski portfolios in the country.

January 25, 2018
Less than two weeks after Alterra is officially named, the company rolls out Ikon Pass, a direct competitor to Vail’s Epic Pass. Priced at $899 then (now $1,099), Ikon gives riders access to all 12 of Alterra’s properties, as well as seven days each at, Jackson Hole (Wyoming), Big Sky (Montana), Killington and Sugarbush (Vermont), and Revelstoke (Canada), plus seven combined days at four of its partner mountains, most notably Aspen Snowmass, which was not included in the original deal with KSL.

June 20, 2018
Six short months later, Alterra makes headlines again by acquiring Utah’s Solitude.

September 6, 2018
In order to grow its portfolio to an even 14 resorts (OK, maybe it was more about keeping up in the competition for snow domination) Alterra buys Crystal Mountain Resort, which boasts the largest and highest lift-serviced terrain in Washington state.

August 2, 2019
In another shot at its counterparts in Broomfield, Alterra snags Arapahoe Basin for the Ikon Pass, which ended its Epic Pass partnership with Vail earlier in the year citing overcrowding in parking lots and other facilities. Ikon Pass holders get seven days of access to A-Basin.

November 13, 2019
After adding access to Sugarbush in the initial Ikon Pass offering, Alterra opted to buy it in a deal that will close in early 2020. Win Smith, CEO of Sugarbush’s parent company Summit Ventures, cited Vail’s recent purchase of Peak Resorts, which operates 10 resorts in the Northeast, and an inability to compete as the final tipping points in his decision to sell. For the 2019-20 season, Ikon Pass holders will only get seven days of access to Sugarbush with the expectation that it will become a full access resort in 2020-21.

Correction 11/21/19: A previous version of this article reported that Alterra acquired Deer Valley on June 20, 2018. Deer Valley was acquired on August 21, 2017, and  Solitude was acquired on June 20, 2018 . 5280 regrets the error.