NASHVILLE, Tenn.— Tennessee's embattled House Speaker Glen Casada announced Tuesday he plans to resign following a vote of no confidence by his Republican caucus amid a scandal over explicit text messages.

Casada had earlier dismissed the text messages he'd exchanged about women with his now-former chief of staff as "locker room talk." "I got caught up in the moment," he told the Nashville Tennessean of the 2016 exchanges earlier this month.

The resignation is unprecedented in Tennessee's modern political era. The last Senate speaker resignation came in 1931. And in 1893, a House speaker declined to resign and his office was declared vacant, according to legislative librarian Eddie Weeks.

"When I return to town on June 3, I will meet with caucus leadership to determine the best date for me to resign as speaker so that I can help facilitate a smooth transition," Casada said in a statement.

Casada announced the decision just a day after previously shrugging off a 45-24 secret ballot vote from his GOP caucus determining they no longer had confidence in his ability to lead the Tennessee House. Casada had said he would work "months" to regain trust from his colleagues and previously spelled out an "action plan" to reassure them.

However, the promise wasn't enough to satisfy critics and instead an increasing number of Republican leaders began demanding he step aside, including a stern warning from Tennessee Gov. Bill Lee saying he would call a special legislative session if Casada didn't voluntarily give up the key spot.

Casada has been dogged by calls to resign since it was revealed he exchanged text messages containing sexually explicit language about women with his former chief of staff in 2016, among other controversies.

Casada's chief of staff, Cade Cothren, resigned from his $199,000-a-year post in early May, after the Tennessean reported he had a history of sending sexually explicit messages and making inappropriate advances toward former interns, lobbyists and campaign staffers. Casada defended Cothren, saying "we all deserve a shot at redemption."

The paper then got a hold of texts Cothren had exchanged with Casada in 2016.

In one exchange obtained by the Tennessean, Cothren wrote that he had sex with a woman in the bathroom of a restaurant.

Casada responded: "Only gone for 60 seconds,” adding, "R u a minute man???;)"

Cothren said, "Yes, I take after you."

Casada was also on other text exchanges where Cothren made derogatory comments about women, the paper reported.

The governor said Tuesday that Casada was making the right call in resigning.

"Speaker Casada has made the right decision, and I look forward to working with the legislature to get back to conducting the people's business and focusing on the issues that matter most to our state," Lee said in a statement.

The resignation announcement marked a quick, turbulent downfall for the Franklin lawmaker who has spent only a few months in the House's top position.

Casada stepped into his role as speaker in January. Bouncing back from a failed bid for speaker more than eight years ago, he received 47 secret ballot votes out of 73 Republicans in the 99-member chamber to become speaker-elect in November.

Casada built up political capital by spending heavily on Republican candidates in contests during the November election, including contested primaries for open Republican seats. He also backed Republican Rep. David Byrd, whom three women have accused of sexual misconduct when he was their high school basketball coach several decades ago.

Casada released digital ads comparing the scrutiny Byrd was under to that given to U.S. Supreme Court nominee Brett Kavanaugh and President Donald Trump.

Byrd was then among more than 40 Republicans whom Casada rewarded with chairmanships of the committee and subcommittee system he expanded. Casada removed Byrd from the post near the end of the last legislative session after protesters showed up at his education subcommittee's meeting for months.

His political support began to waver when Cothren was pressured into resigning after the release of years-old racist texts and the sexually explicit messages, and Cothren's admission that he used cocaine in his legislative office years before becoming Casada's top aide. Casada was included in one of the group texts with a racist message, but has said he never saw it.

Another scandal that sparked early doubts was the report of possible evidence tampering by Cothren with a young black activist's criminal case, which a special prosecutor is still investigating.

Casada denied that tampering allegation and a variety of others that continued to pile up, ranging from accusations that he spied on legislative members to a GOP colleague's claim that Casada tried to "rig and predetermine" an ethics review regarding his controversies.

About a week ago, he addressed his fellow GOP House members about the texts and other issues, assuring them there was "nothing else to come out." Just days later, another text exchange emerged in a WTVF-TV report, in which he and Cothren — then the House Republican caucus press secretary — joked about the ages of two women and asked if they were 21 years old.

According to the texts, Cothren responded that "it only takes 18," Casada answered "Lol!!! And true!"