Original: Alsace is frequently mentioned in conjunction with Lorraine, because German possession of parts of these two régions (as the province Alsace-Lorraine, 1871–1918) was contested in the 19th and 20th centuries, during which Alsace changed hands four times between France and Germany in 75 years.
Simplified: Alsace is frequently mentioned in conjunction with Lorraine, because the possession of these two régions (as Alsace-Lorraine) has been often contested in 19th and 20th century history.