What battle convinced the French to declare war on the British?

Saratoga Leads to Full Alliance In December 1777, news reached France of the British surrender at Saratoga, a victory that convinced the French to make a full alliance with the revolutionaries and to enter the war with troops.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

thomas jefferson is the answer