Minnesota became the 32nd state to join the Union on May 11, 1858. Minnesota’s first two senators, Henry Rice and James Shields, took office on that day. Minnesota’s longest-serving senators include Knute Nelson (1895-1923) and Henrik Shipstead (1923-1947). Among those who rose to leadership positions are Hubert Humphrey and Walter Mondale. Humphrey served as party whip, deputy president pro tempore of the Senate, and vice president of the United States. Mondale also served as vice president—the Senate's constitutional president or presiding officer.