History was first to market with its Navy SEAL drama series Six, which was a breakout hit when it debuted in early 2017, quickly earning a second-season renewal.

At the time of Six‘s Season 2 renewal in March 2017, military dramas was already a hot trend, with three broadcast drama pilots in the genre ordered. Beating the odds, all three, CBS’ SEAL Team, NBC’s Brave and the CW’s Valor, made it to series, which all premiered in fall 2017. While Brave and Valor did not get back back orders and only lasted one season, SEAL Team, starring David Boreanaz, has been reasonably successful, airing a full-season 22 episode freshman run and getting renewed for Season 2.

“We are incredibly proud of Six,” History EVP Programming Eli Lehrer told Deadline at TCA today. “I think what we found is, between the end of Season 1 and the launch of Season 2, the marketplace became incredibly crowded with similar, one may say derivative, shows. When we came back for Season 2, it made it challenging for our series to reestablish itself.  We saw a decline in the ratings as a result.”

Because of all the competition, History delayed the Season 2 debut of Six until after the end of the broadcast season in late May. Still, ratings have dropped in Season 2, running 50% below the Season 1 averages in Live+same day, leading to History’s decision last month to cancel the series.

The cancellation is not a reflection of Six‘s quality, Lehrer was quick to point out. “We were very happy with the show creatively; if I anything I think Season 2 was ever better than Season 1,” he said. “But I think in such a crowded marketplace, it is harder to get people’s attention as they had spent a season watching SEAL Team on CBS, Valor and The Brave. As a result, our show felt less unique in the marketplace.”

From A+E Studios, Six followed Navy SEAL Team Six led by Joe ‘Bear’ Graves (Barry Sloane) in a mission to destroy the terrorist network responsible for the shooting of their former team leader Richard “Rip” Taggart (Walton Goggins). The Season 2 — and now series — finale airs next Wednesday.

History’s scripted series portfolio includes flagship Vikings, Knightfall, which I hear is gearing up for a second season, and the upcoming Robert Zemeckis-produced UFO series Blue Book.