Thus Semiramis, Queen of Nineveh, raised a mound over the tomb of Ninus, her husband. Stones were likewise piled up over the remains of Laïus, father of Oedipus. In the 'Iliad,' Homer speaks of the mounds that were raised to the memory of Hector and Patroclus. That dedicated to Patroclus--the pious work of Achilles--was more than 100 feet in diameter. Homer speaks of the _tumuli_ existing in Greece, which, even in his time, were considered very ancient, and calls them the tombs of the heroes. A _tumulus_ was raised by Alexander the Great over the ashes of his friend Hephæstio, and so great were the dimensions of this monument that it is said to have cost 1200 talents, that is about £240,000 of our money. In Roman history, too, we find instances of the same kind. Lastly, the pyramids of Egypt, those costly and colossal funeral monuments, are the still visible representations of the highest expression of posthumous homage which was rendered by the generations of antiquity to their most illustrious and mighty men. This, however, could not have been in every case the prevailing idea in the men of the Stone Age, in causing the construction of these _tumuli_. The large number of bodies which have been found in some of these monuments completely does away with the notion that they were raised in honour of a single personage, or even of a single family. They were often sepulchres or burial-places common to the use of all. Among this class we must rank the _tumuli_ of Axevalla and of Luttra, situated not far from one another in Sweden. The first, which was opened in 1805, contained twenty tombs of an almost cubical form, each containing a skeleton in a crouching or contracted attitude. When the second was opened, the explorers found themselves in the presence of hundreds of skeletons placed in four rows one upon another, all in a contracted position like those at Axevalla; along with these human remains various relics of the Stone Age were also discovered. [Illustration: Fig. 145.--Position of Skeletons in a Swedish Tomb of the Stone Age.] Fig. 145 represents the position in which the skeletons were found. M. Nilsson has propounded the opinion that the "passage-graves" are nothing but former habitations, which had been converted into tombs after the death of those who had previously occupied them. When the master of the house had breathed his last--especially in the case of some illustrious individual--his surviving friends used to place near him various articles of food to provide for his long journey; and also his weapons and other objects which were most precious to him when in life; then the dwelling was closed up, and was only reopened for the purpose of bearing in the remains of his spouse and of his children.