A rocking chair used by president John F. Kennedy at the White House and two flags from his office drew more than $500,000 from a collector, Heritage Auctions said Sunday. They were among some 228 items linked to the former president put under the hammer late Saturday in Dallas, Texas, on the 50th anniversary of JFK's assassination in that city. The two flags -- an American flag and one with the presidential seal -- were sold for $425,000, four times their pre-auction estimate, Heritage said in a statement. The rocking chair sold for $87,500, also well above the pre-auction estimate of $50,000. The items were owned by Dean William Rudoy, a volunteer in Kennedy's 1960 presidential campaign who collected memorabilia of the slain president over the past 50 years. The flags and rocking chair were bought by a collector from the U.S. Southwest who "thought it important that these two lots stay together," said Tom Slater, historical auctions director at Heritage. He attributed the high price to the "affection and regard" people hold for JFK and to the fact that "presidential flags of any kind are tremendously sought after by collectors." The cushioned rocking chair was stationed in the office of Kennedy's personal secretary, Evelyn Lincoln. But it was often brought into the Oval Office so that Kennedy, who suffered from chronic back pain, could use it during his meetings and long hours at work. The two flags, which were positioned behind his desk, were given to Kennedy's secretary five days after the president's death, at the request of his widow, Jacqueline Kennedy. Kennedy was assassinated at the age of 46 on November 22, 1963, less than three years after taking office. The 50th anniversary of his death prompted numerous events in the U.S. in recent weeks, including a relatively modest ceremony in Dallas on Friday. His killer, 24-year-old Lee Harvey Oswald, was arrested less than three hours after the shooting. He was shot to death on live television two days later as he was being transferred to the county jail.