WASHINGTON -- The Senate, the institution Robert C. Byrd cherished and chronicled like no other, paused Monday to honor its longest-serving member.

Mr. Byrd's desk, directly behind the majority leader's because of his seniority, was draped in a black cloth as the Senate session opened Monday afternoon. Atop the desk was a vase of white roses. Colleagues from both parties honored him in floor speeches and remarks during the Elena Kagan Supreme Court confirmation hearing.

The Democrat's impact on the upper chamber was profound during a record 51 years in office representing West Virginia. Those years in the Senate, added to his six years in the House of Representatives, made him the longest-serving congressman as well.

But Mr. Byrd's influence wasn't measured simply in how long he held the seat, or in his positions as majority and minority leader, Appropriations Committee chairman and president pro tempore of the Senate.

His colleagues remembered Mr. Byrd most of all for his mastery and love of the chamber's history, quirky rules and customs, expressed in remarks and in a four-volume history of the Senate that Mr. Byrd wrote.

"Some people pass through this institution, experience this institution," said Sen. Jay Rockefeller, D-W.Va. "He lived this institution."

The respect for Mr. Byrd extended across the country and across the aisle, with senators citing their admiration of his sharp wit, encyclopedic knowledge of world history and his devotion to the Constitution.

"He not only wrote the book on it, he was a living repository of its rules, its customs and its prerogatives," said Minority Leader Mitch McConnell, R-Ky.

"So it would be a mistake to think that Sen. Byrd became synonymous with the Senate simply because he served in it longer than anybody else. Rather, it was a fitting coincidence that a man who cherished and knew this place so well would become its longest-serving member."

Mr. Byrd was known as a shrewd power broker in leading his party -- both in the majority and minority -- and when he ran the Appropriations Committee, which he used to steer incredible amounts of federal dollars to his home state. Though he was often an outspoken and fierce partisan, he earned friends from both parties for his advocacy for the Senate itself.

Mr. Byrd won a battle in the late-1990s against the line-item veto, which he felt would diminish the power of Congress, and was fond of saying he served alongside 12 presidents, rather than under them.

Sen. Arlen Specter, D-Pa., a history buff himself who speaks often about the need to maintain the Senate's powers, mourned the loss of the Senate's "colossus."

"It means some of the rest of us will have to step up and protect the Constitution," Mr. Specter said.

Mr. Byrd, who was elected to the Senate before many current senators were born, became a mentor to generations of members.

"Sen. Byrd often reminded us that United States Senate is still the anchor of the Republic," said Majority Leader Harry Reid, D-Nev.

"Well, Robert Byrd was the anchor of the Senate. There will never be another like him."

Washington correspondent Daniel Malloy writes the "Pittsburgh On The Potomac" blog exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.