Many same-sex couples said they would wait to apply for their licenses, which expire after 65 days, to have time to prepare for wedding celebrations in the spring and summer. Indeed, advocates for same-sex marriage predicted that there would not be the same rush for licenses on Wednesday that there was in 2004, when Massachusetts became the first state to legalize gay marriages, or in June, when California began performing them. They cited both the short notice and the fact that Connecticut has, since 2005, offered civil unions, which offer similar rights and benefits, for gay couples.

Still, lawyers and supporters of gay marriage called the day momentous, especially as a counterpoint to the passage last week of a ballot measure in California that invalidated a court decision legalizing gay marriage. Connecticut voters overwhelmingly rejected a proposal, backed by opponents of same-sex marriage, for a constitutional convention that would allow for such direct voter initiatives on the ballot.

“Today Connecticut sends a message of hope and promise to lesbian and gay people throughout the country who want to be treated as equal citizens by their government,” said Ben Klein, a senior lawyer with Gay and Lesbian Advocates and Defenders, a Boston-based group that litigated the Connecticut case. “It’s living proof that marriage equality is moving forward in this country.”

City Hall here was adorned with bunches of white balloons and giant sprays of long-stemmed red roses as Robin and Barbara Levine-Ritterman, who were among the eight named plaintiffs in the lawsuit against the state, obtained a marriage license, although they did not plan to marry immediately. “We’re thinking about doing it in May,” said Robin Levine-Ritterman, 49, a naturopathic physician and acupuncturist. “But we really wanted to be part of this historic first.”

But Ms. Oliveira, 36, a yoga teacher and early childhood education consultant, and Ms. Vickery, 44, a lawyer, did not wait. Officiating at the simple ceremony, just before 11 a.m., was their friend, Judge F. Herbert Gruendel of the State Appellate Court, who recalled Ms. Oliveira’s saying five years ago on his porch that she would like to be married. “Today I can say to you that you are,” he said.