San Francisco celebrated the 'Winter of Love' 14 years ago

SAN FRANCISCO (KGO) -- The fight to legalize same-sex marriage is becoming a hot topic in this year's California governor's race.

Lt. Governor Gavin Newsom launched a new advertisement in which he highlights his involvement in legalizing same-sex marriage.

It was 14 years ago Monday that Newsom, who was San Francisco mayor at the time, authorized the county clerk to issue marriage licenses to gay and lesbian couples.

RELATED: 14th anniversary of SF's historic move to marry same-sex couples

Following is a timeline of how that decision eventually led to same-sex marriage becoming legal in the entire country.

2004

Feb. 12: San Francisco begins issuing same-sex marriage licenses.

Mar. 11: The California Supreme Court orders San Francisco to immediately stop performing same-sex marriages while it reviews the legality of Newsom's authority. San Francisco sues the state in San Francisco Superior Court, claiming the ban on same-sex marriage is unconstitutional.

Aug. 12: The state Supreme Court rules that San Francisco overstepped its authority by allowing same-sex marriages. The court voids all marriage certificates issued by the city.

2005

May 15: The California Supreme Court overturns a state law that defines marriage as a union between a man and a woman. effectively legalizing same-sex marriage in the state.

June 17: Counties across California begin issuing same-sex marriage licenses.

Nov. 4: Voter approve Proposition 8, which again put an end to same-sex marriages in the state.

2012

Feb. 7: A three-judge panel of the Ninth District Court of Appeals rules that Proposition 8 is unconstitutional. Opponents of same-sex marriage appeal to the U.S. Supreme Court.

2013

June 26: The U.S. Supreme Court dismisses the appeal. The next day, the court struck down the Defense of Marriage Act (DOMA) that prohibited same-sex couples from collecting federal benefits.

June 28: The Ninth Circuit Court of Appeals lifts a stay on same-sex marriages. Counties resume issuing same-sex marriage licenses.

2015

June 26: The United States Supreme Court rules that states cannot ban same-sex marriage, making it legal in all 50 states.