How did Ireland win 2009’s Six Nations?

Question

Ireland ended a wait of 61 years to win a Grand Slam at the 2009 Six Nations. They began in earnest with a 30-21 victory against France on the opening weekend before a comprehensive 38-9 win in Rome. A narrow 14-13 victory against England was the closest they came to defeat, but they done enough to ensure their third consecutive win. Ireland made it four with a 22-15 win against Scotland at Murrayfield before making history at the Millennium Stadium with a pulsating 17-15 victory against Wales.