the Official History. The preliminary artillery barrage at Messines was also significant: in the week prior to the attack British artillery fired more than 3.5 million shells of various sizes onto the ridge at Messines. Following the mine detonation, and advancing behind a creeping artillery barrage, nine divisions attacked the ridge from three sides. By mid morning on 7 June all objectives had been taken in the limited offensive, although Australian, New Zealand and British troops fought off German counterattacks for about a week. Australian participation in Messines consisted of the 3rd and 4th Divisions; the New Zealand Division also played a key role in the battle, being the Division that actually took the village of Messines. The two Australian divisions suffered 6800 casualties in the two-week battle. Messines was startling success compared to the Third Battle of Ypres (July -- November 1917). One of those huge, costly and largely unsuccessful battles of the Western Front, Third Ypres cost hundreds of thousands of British, Australian and Canadian casualties (and hundreds of thousands of German casualties), with little change in the strategic situation. At the end of the battle, and after three months, the Allies had gained just few miles of ground; German forces would subsequently retake this ground over a couple of weeks in April 1918. Of the eight or so sub battles that made up Third Ypres, Australian forces were most heavily involved in the following: Between the start of August and end of November 1917 the Australian forces