Historians have discovered the number of soldiers sent to fight in the bitter Gallipoli campaign in World War One was far greater than originally thought.
It's now believed about 17,000 soliders landed on the Turkish Peninsula. That's double the original estimate of 8,566 Kiwi soldiers.
Defence Force historian John Crawford says it's a significant discovery.
"It gives us a completely different picture of how that campaign was fought."
"Up to now it's been seen as quite a small New Zealand contribution to the campaign - only a few thousand men.
"This research effectively dulls that number. It means it's twice as significant."
The research shows that nearly one in five Kiwi soldiers served at Gallipoli.
The breakthrough for the researchers trying to solve a 100-year-old mystery was a set of three notebooks, filed away in the National Archives.
They were written by an officer whose task was to record all the troops coming on and off the peninsula.