The Secret Service remained connected to the Johnson family for forty-six years, beginning on January 20, 1961, when Lyndon Johnson was inaugurated as vice president. During those years, agents witnessed many events in Washington and Texas. A critical turning point came with the assassination of President John F. Kennedy on November 22, 1963, which launched Lyndon Johnson’s presidency. Over the next five years, the Secret Service protected President Johnson around the clock from protestors, riots, fires, and assassination. That protection continued after he left the White House in 1969 and returned to the LBJ Ranch. After Lyndon Johnson died of a heart attack on January 22, 1973, agents remained to protect former first lady Lady Bird Johnson. Her protection continued until her death on July 11, 2007, making her at the time the longest protected first lady of the twentieth century.