Queen Elizabeth II's husband, Prince Philip, remained in the hospital Saturday following a chest infection, Buckingham Palace said. Philip, 86, suffered from a bad cold that worsened in recent days, palace officials said Friday. A spokeswoman for the palace said Saturday she would not be giving an update on his condition. But the spokeswoman added that the prince's engagements Monday evening had not been canceled, which suggests that Philip was expected to be out of the hospital by then. She spoke on condition of anonymity in line with palace policy. The prince was taken to the hospital at 5 p.m. Thursday, but the news was not made public until Friday afternoon. Officials said Friday that Philip had traveled to the hospital by private car and was strong enough to walk into the building without assistance. They said he was able to read and answer letters from his bed. The palace spokeswoman said Philip was being treated by the Physician to the Queen, Dr. John Cunningham. Well-wishers visited Saturday to deliver flowers, including five-year-old Sarah Bithell, who handed a bouquet to the police officer on guard outside the hospital. Last week, the prince looked well as he joined the queen in saying goodbye to French President Nicolas Sarkozy and his wife, Carla Bruni-Sarkozy, at the end of their two-day state visit, although he missed a memorial service Wednesday for Sir Edmund Hillary, the first man to conquer Mount Everest. An active man who has enjoyed good health well into his 80s, Philip is known as the queen's constant companion at public events - and as the master of the royal gaffe. He once told a group of British students in China: "If you stay here much longer you'll all be slitty-eyed." On another occasion he asked a Scottish driving instructor: "How do you keep the natives off the booze long enough to pass the test?" A member of the Greek royal family, Philip was evacuated from the country by Britain's Royal Navy in 1922 following the abdication of King Constantine, his uncle. Educated in France, Germany, and Britain, he joined the Royal Navy in 1939 and saw active service throughout World War II. Philip and Elizabeth married in 1947, when she was still a princess. He gave up his naval career when she became queen and has no constitutional role other than as one of the queen's privy counselors. Philip is a great-great-grandchild of Queen Victoria.