Complex sentence: The 23rd Battalion was an infantry battalion of the Australian Army that served in World War I. Raised in 1915 as part of the First Australian Imperial Force as the third battalion of the 6th Brigade, attached to the 2nd Division.
Split into simpler sentences: The 23rd Battalion was an infantry battalion of the Australian Army. It was raised in 1915 as part of the First Australian Imperial Force for service during World War I and formed part of the 6th Brigade, attached to the 2nd Division.