Senate Parliamentarian Alan Frumin’s retirement today is paving the way for the first woman to hold that post in the history of the chamber.

On Wednesday, Elizabeth MacDonough is expected to take over as parliamentarian, the person responsible for advising the entire Senate on its arcane rules and procedures.

MacDonough is serving as senior assistant parliamentarian, a position she has held since 2002. She served as an assistant parliamentarian from 1999 to 2002. Although there have been women in those positions in the past, MacDonough outlasted them.

Former Senate Parliamentarian Robert Dove said he believed he had hired the first female and the first African-American candidates for parliamentarian in the office long ago. “There are several people who have come into the office and decided that the requirements were simply too much,” he said, citing hires he made to the parliamentarian’s office in the 1980s.

“The demands are, frankly, tremendous,” Dove said of the position. “What the parliamentarian says is the law. There’s a huge responsibility there.”

Dove is confident that MacDonough, whom he hired while heading the office, will excel at the job. The only way to prepare for the job is to do it, he explained. “You really learn how to be parliamentarian by being in the office.”

And MacDonough has been in the office for 11 years, which Dove said will be to her advantage. “She’s quite aware of how demanding the job is.”

MacDonough declined to be quoted for this article.

The Secretary of the Senate, who is appointed by the Majority Leader, oversees the Senate parliamentarian. Traditionally, the title of parliamentarian has gone to the most senior member of the parliamentarian’s office, without interference from the Secretary of the Senate or Senate leaders.

The parliamentarian largely flies under the radar, making sure presiding officers know the rules and ruling on the germaneness of amendments, among other things.

But in recent history, the position has attracted some controversy.

In 2010, Frumin was in the center of the health care reform debate because his rulings on what was permissible in a budget reconciliation bill had the potential to throw Senate consideration into chaos. At one point, Capitol Police took steps to ensure Frumin’s safety because tea party activists had threatened to picket his house.

But the highest-profile dustup in the parliamentarian’s office came in 2001 when Dove — who first became Parliamentarian in 1981 and took the title again in 1995 — was dismissed from the position by then-Secretary of the Senate Gary Sisco at the behest of then-Majority Leader Trent Lott (R-Miss.). Lott reportedly disagreed with Dove’s rulings on budget reconciliation. Frumin replaced Dove both in 1987 and in 2001.

Senate leaders are expected to address MacDonough’s ascension and formally thank Frumin for his service today in speeches on the floor.

Emily Pierce and Niels Lesniewski contributed to this report.