In five minutes from that time both the boys were fast asleep. CHAPTER XIII. THE PALACE OF HOLYROOD. While Mr. George and the boys were in Edinburgh, they went one day to visit the Palace of Holyrood, and they were extremely interested in what they saw there. This palace stands, as has already been stated, on a plain, not far from the foot of a long slope which leads up to the castle. As long as Scotland remained an independent kingdom, the Palace of Holyrood was the principal residence of the royal family. Queen Mary was the last of the Scottish sovereigns--that is, she was the last that reigned over Scotland alone--for her son, James VI., succeeded to the throne of England, as well as to that of Scotland. The reason of this was, that the English branch of the royal line failed, and he was the next heir. So he became James the First of England, while he still remained James the Sixth of Scotland. And from this time forward the kings of England and Scotland were one. Mary, therefore, was the last of the exclusively Scottish line. She lived at Holyrood as long as she was allowed to live any where in peace; and on account of certain very peculiar circumstances which occurred just before the time that she left the palace, her rooms were never occupied after she left them, but have remained to this day in the same state, and with almost the same furniture in them as at the hour when she went away. These rooms are called Queen Mary's rooms, and almost every body who visits Scotland goes to see them. The reason why the rooms which Mary occupied in the Palace of Holyrood were left as they were, and never occupied by any other person after Mary went away, was principally that a dreadful murder was committed there just before Mary quitted them. This, of course, connected very gloomy associations with the palace; and while great numbers of persons were eager to go and see the place where the man was killed, few would be willing to live there. The consequence has been, that the apartments have been vacant of occupants ever since, though they are filled all the time with a perpetually flowing stream of visitors. The circumstances of the murder were very extraordinary. Mr. George explained the case briefly to the boys during their visit to the palace, as we shall presently see. On leaving the hotel they went for a little way along Prince's Street. On one side of the street there was a row of stores, hotels, and other such buildings, as in Broadway, in New York. On the other side extended the long and deep valley which lies between Prince's Street and Castle Hill. The valley was crossed by various bridges, and beyond it were to be seen the backs of the lofty houses of High Street, rising tier above tier to a great height, looking, as has already been said, like a range of stupendous cliffs, lifting their crests to the sky.