Celtic F.C. their sixth successive league title on 2 April 2017, with a record eight league games to spare. As Celtic's unbeaten domestic run continued, they subjected Rangers to their heaviest defeat at Ibrox since 1915, 5–1, on 29 April. Celtic's 2–0 win over Hearts on 21 May saw them finish 30 points ahead of second-placed Aberdeen in the league, with a record 106 points, and the team became the first Scottish side to complete a top-flight season undefeated since Rangers in 1899. On 27 May 2017, Celtic clinched their fourth treble by defeating Aberdeen 2–1 in the Scottish Cup final. The
Celtic F.C. and World War I in British football that stood for a century. However, football was not as important due to the War effort; attendances fell, player's salaries were reduced and there was increased pressure to complete the fixture list. On one occasion in 1916, during their 62 match unbeaten run, Celtic had to play two matches on the same day against Raith Rovers and Motherwell, and won both 6–0 and 3–1 respectively. Recruitment drives were also held at football matches and on one occasion an exhibition of trench warfare was held at Celtic Park. Over 50 contracted and former Celtic players served in the