At no point during this, her 4-year-old campaign, had Treve looked like the filly who had won the 2013 Prix de l’Arc de Triomphe by five lengths. Until Sunday. And then – suddenly, unexpectedly, decisively, and wonderfully – the Treve of old returned. She burst to the lead with a quarter-mile to go and won the Arc for the second year in a row, a remarkable form reversal from a filly many thought would never win again.  Treve became the first horse since Alleged in 1977 and 1978 to win consecutive Arcs. She was not quite as explosive this year as last, but her margin of victory still was two lengths, and Treve never looked in danger after making the front without being asked at the top of the Longchamp homestretch. From there, Treve bounded home under hearty encouragement from Thierry Jarnet, whose fourth Arc win came 22 years after his first on Subotica in 1992. Flintshire ran the race of his life to nab second, 1 1/4 lengths in front of the 3-year-old filly Taghrooda, who was hung wide the entire trip. Kingston Hill, the English Derby runner-up and St. Leger winner, had an even worse draw than Taghrooda and ran well to get fourth. The Japanese were again denied a greatly desired Arc win, with 3-year-old filly Harp Star – put into the race far too late by her rider -- in sixth, bettering eighth-place Just a Way and 14th-place Gold Ship. French 3-year-old filly Avenir Certain took the first loss of her career, finishing 11th, while her well backed 3-year-old stablemate Ectot, faded to 17th. Treve, purchased from the Head family by Sheikh Joaan al Thani’s Al Shaqab Racing during the summer of 2013, almost certainly made her final start Sunday, though trainer Criquette Head-Maarek left open the slimmest chance of one further race this year. She was timed in 2:26.05 for 1 1/2 miles on good going, the second-fastest Arc in the last 10 years. Ground that firm was supposed to work against Treve, who had battled foot and back problems this season. Her 2014 debut had produced a good second to the excellent Cirrus des Aigles, but Treve then finished a tame third in the Prince of Wales’s Stakes and fourth in her Arc prep, the Prix Vermeille. It would have been no surprise had Treve’s retirement been announced after the Vermeille, but Head-Maarek pushed on, asserting after a final major workout this week that Treve had a decent chance to get back to her best in the Arc. And she was right. Saving ground all the way while racing in mid-division, Treve got a great trip under Jarnet, and she made the most of it. The win was her sixth from nine starts and earned her the winner’s share of a $6.2 million purse. More than that, it changed her place in racing history. Before Sunday, Treve was merely a brilliant Arc winner, a filly who had taken advantage of a major weight break in 2013 because of her age and sex, and who had failed to train on at 4. Sunday, she staked a much greater claim