“Bartolomeo Ammanati, a Florentine architect and sculptor, sent expressly by the grand duke, presented himself before the pope, without either models or designs, and requested a year to consider it; for this he was most severely reprimanded by the pontiff.  Fontana exhibited his wooden model, with a leaden pyramid, which, by means of a windlass and crane, was raised and lowered with the greatest facility; he explained the nature of these machines and movements, and gave a practical proof of their capability by raising a small pyramid in the mausoleum of Augustus, which was in a ruinous condition.  After many disputes, Fontana’s invention was approved; but, as he had not yet acquired a name of sufficient importance, the execution of it was committed to two architects of renown, Giacomo della Porta and Bartolomeo Ammanati.—­These immediately commenced a scaffold in the centre of the square where the obelisk was to stand.

“Fontana being justly displeased that his own discovery should not be entrusted to his execution, went to the pope, and respectfully represented to him, that no one could so properly execute a design as the inventor.  Sixtus was persuaded, and committed the entire direction of it to him.  The architect then commenced his work with the utmost celerity.  He dug a square hole of 44 feet, in the piazza, 24 feet deep, and finding the soil watery and chalky, he made it firm by strong and massive piles.  At the same time he had ropes made, three inches in diameter, 1500 feet long, an immense quantity of cords, large iron rods to strengthen the obelisk, and other pieces of iron for the cases of the cranes, pins, circles, pivots, and instruments of every kind.  The iron to secure the obelisk alone amounted to 40,000 lbs., and was made in the manufactories of Rome, Ronciglione, and Subbiaco.  The beams, taken from the woods of Nettuno, were of such a prodigious size, that each was drawn by seven pair of buffalos.  From Terracina, elm was brought, for the caseing, and Holm oak for the shafts of windlass; and to prevent the ground from giving way, it being soft and marshy, in consequence of the great weight, he made a bed with two layers of timber, crossing each other in a contrary direction.  On this foundation he placed the castle or carriage, which had eight columns:  each of these columns was composed of so many thick planks, that they measured 13 feet in circumference.  These were united together by thick cords, without screws, in order to be done and undone with greater quickness.  The height of the beams was required to be 90 feet; and not any being of that length, they were placed one on the other, and united by iron bands.  These columns were strengthened by forty-eight braces, and tied together on all sides.  The obelisk was entirely covered with double mats, to prevent its being injured; it was then surrounded by planks, over which were placed large rods of iron, and these embracing the thick part underneath, came directly over the four faces of the mass, which thus became totally encircled with these coverings.  The whole pyramid thus weighed one million and a half pounds.  Fontana calculated that every windlass, with good ropes and cranes, would be able to move 20,000 lbs. weight; and consequently forty would move 800,000, and he gained the rest by five levers of thick beams 52 feet long.