Usher in
Definition 1 of 1
Pro Tip 1/3Transitional Moment
Implies a notable transition from one period to another, often historical or significant. 
The fall of the Berlin Wall ushered in a new era of freedom.
Pro Tip 2/3Start of Change
Indicates the beginning of change, not just the continuation of something already happening. 
The CEO's decision ushered in a complete restructuring of the company.
Pro Tip 3/3Positive Connotation
Often suggests positive progress or innovation, like the start of something better. 
The treaty ushered in a period of unprecedented peace.