Here's a timeline of key events that led to the formation of the gang:
* 1869: Ned Kelly's father, Red Kelly, is killed by police during a fight. This event sparked a deep resentment towards the police in Ned Kelly.
* 1870s: Ned Kelly and his associates, including Dan Kelly, Joe Byrne, and Steve Hart, become involved in petty crimes and eventually escalate to armed robbery to survive.
* 1878: The Kelly Gang's notoriety grows with the infamous "Stringybark Creek" incident, where three policemen are killed.
* 1879: The Kelly Gang becomes an outlaw group with a strong sense of social justice and a desire to fight against the perceived corruption of the police.
Therefore, it's difficult to pinpoint an exact date for the formation of the Kelly Gang. It gradually emerged as a group of outlaws during the 1870s.