A legal battle over gay marriage in Colorado could reach a head soon. A judge will hear arguments Wednesday from the state's attorney general, who wants the Boulder County clerk to stop issuing marriage licenses to same-sex couples.

Legal recognition of gay relationships in Colorado has a long history, beginning in 1975 when Boulder County issued the state’s first marriage license to David McCord and David Zamora. The license was later revoked by the attorney general.

Our timeline of recent events begins in 2006, when the Colorado Definition of Marriage Initiative was voted into law, and continues through the present day. Scroll through the interactive timeline to view milestones that mark the history of gay marriage in Colorado.