The period is usually considered to have begun in July/August 1915 and ended in early 1916, with the arrival in numbers of the Allied Nieuport 11 and DH.2 fighters; less accurately, it is sometimes extended to the whole period of service of the Fokker monoplanes on the Western Front – from the arrival of the first two Fokker E.I fighters at FA62 in June 1915, until the final disappearance of the last Eindeckers from the early Jagdstaffeln in August/September 1916.