sentences:  During the New Zealand Wars, although the colony had no official role, New South Wales contributed significantly to the 2,500 volunteers that were sent from Australia in 1863.The 1850s and 1860s saw further development of the system of defensive fortifications around Sydney.As a result of concerns about Russian attack, the construction of Fort Denison was completed and in 1856 gunners from the Royal Artillery arrived to man the defences.