The name of this holiday literally translates to June 7th.  

After WWI, when industry and agriculture were disrupted across the whole continent, the colonial government of Malta failed to provide the basic provisions for the islands. This scarcity and an increased military presence on the island led to the rich getting richer, while most citizens of Malta did without. 

This lead to civil unrest and a demand for higher wages. In 1919, the National Assembly met to consider a resolution that would mean independence from Great Britain. This was brought forward by the nationalist faction and was opposed to the original resolution. 

The second National Assembly was set for June 7th that same year and the crowd that had been gathering was set in motion when the Union Jack was flown above the A la Ville de Londres flag. The crowd proceeded to break windows, remove the Union Jack wherever they found it, and assault officers and soldiers. 

Reinforcements were brought in and the soldiers would end up shooting into the crowd. Four people were killed and fifty people would end up being injured. This would lead to the British colonial government being challenged.