The lateran obelisk comes from Tebe, Egypt, where it was placed in Ammone's temple. It was erected almost simultaneously with the obelisk of Piazza San Pietro in front of the Vatican Basilica made by the architect Domenico Fontana. "The Lateran obelisk takes his name from the nearby basilica of San Giovanni in Laterano: this obelisk was ordered by Ramses, son of Sothis, king od Egypt...when they hoisted it on, it risked falling down, because of the weight of such a huge mass. Therefore, the king ordered that his son the tied on top of it, so that the need to safe the royal child might make the architect more careful. It was later raised in Tebe, in the temple of the Sun, to which is was devoted until 334 b.c.,at the time of the Emperor Costanzo, son of Costantine the Great... who took it away and sent it to Alexandria: however, fate disappointed the Emperor's wishes. Indeed, after the death of Costantine, the obelisk stayed for a long time on Alexandria, ignored by everybody. Later on Costanzo, heir of his father's glory, ordered to take it to Rome and hoist it in the middle of the Circo Massimo , where it stayed for a long time, until the Goths invaded Rome. At that point, it collapsed and layed down on the ground until Pope Sixtus, once he recognised its value, had it unearthed, and raised once again in the Piazza del Laterano (1588), where we can still admire it now." [G. de Sepi, 1678, " Obeliscus Pamphilius, hoc est, interpretatio Nova..." translated by Roberto Buonanno op.: The stars of Galileo Galilei and the Universal Knowledge of Athanasius Kircher.] The hieroglyphic inscriptions deal with the Pharaoh of the XVIII dinasty of Tutmosis III and IV of the XV century b.C.[Source: "Athanasius Kircher's theatre of the world" by Joscelyn Godwin].
The obelisk was ordered by the Egyptian king Ramses I (ca. 1345 b.C.– June 1290/1289 b.C.), who was son of Sothis, head of the archers, and belonged to a warlike aristochracy from Nile delta. [Source: Kenneth A. Kitchen, "Il Faraone trionfante", Laterza, Bari (1994). p.29b]
Ferdinand III (13 July 1608 – 2 April 1657) was Holy Roman Emperor from 15 February 1637 until his death, as well as King of Hungary and Croatia, King of Bohemia and Archduke of Austria. He was Kircher's (Geisa, 2 May 1602 – Rome, 28 November 1680) patronus since the 1643 publication of "Lingua Aegyptica restituta", from which Kircher started his Egyptian studies on obelisks. Thanks to his financial support, Kircher published also "Oedipus Aegyptiacus". Because of that, Kircher dedicated his work on Lateran obelisk to him (infact on Lateran obelisk's press there is an iscription of Ferdinando III).
Athanasius Kircher, following Oropollo's studies (V sec. a.C, author of "Hieroglyphica") about two hundred hyrogliphical letters,understoond that the Egyptian language comes from Copto and the hyrogliphicy has a symbolic value. Kircher wrote about it: "Avendo seguito i significati reconditi esposti dagli autori…come un filo di Arianna, avvalendoci dell’aiuto della scienza analitica o combinatoria, mediante gli sforzi e le indagini di molti anni, alla fine, guidati e condotti da Dio, abbiamo penetrato gli arcani ed i misteri dei geroglifici” ( Ob. Pamph. Epist. Paraen. ad Fi.).
Although Kircher's approach to deciphering texts was based on a fundamental misconception, some modern commentators have described Kircher as the pioneer of the serious study of hieroglyphs. In fact he published a vocabulary of Copto, Latin and Arabic organized in parallel columns consulting the information took by the traveller Pietro della Valle. The data which he collected were later consulted by Champollion in his successful efforts to decode the script. Kircher himself recognized the possibility of the hieroglyphs constituting an alphabet; he included in his proposed system derivations of the Greek alphabet from 21 hieroglyphs. According to Joseph MacDonnell, it was "because of Kircher's work that scientists knew what to look for when interpreting the Rosetta stone" ( MacDonnell, p 12). Another scholar of ancient Egypt, Erik Iversen, concluded: "It is therefore Kircher's incontestable merit that he was the first to have discovered the phonetic value of an Egyptian hieroglyph. From a humanistic as well as an intellectual point of view Egyptology may very well be proud of having Kircher as its founder"( Iversen, pp 97–98).
[Sources: https://www.cicap.org/n/query.php?id=86 and http://liceoeqvisconti.gov.it/files/RMPC080007/Museo/obelischi_kircher.pdf]
For a Kircher's detailed study of ancient Egypt consult the book "Athanasius Kircher, A Renaissance Man and the Quest for Lost Knowledge" by Joscelyn Godwin from page 21.
Mesuarement: palmo equals 25-26 cm; libra equals 0,45359 kg [source: Dizionario Treccani]. Hight: 31,68 m; Pyramidion: 3,08 m; major side of the lower base: North and South 2,915 m; minor side of the lower base: West and East 2,6466 m; major side of the upper base: 2,05 m; minor side of the lower: 1,705 m; weight: 349518,831 kg.
Structure: The obelisk is the ancientest, the highest and the weightest. It is made up of pink granite. At the top right of the page we can find the inscription "iconismus tomo III. Fol. 161 inserendus", referred to the third volume of the 1654 edition of the Kircherian work "Oedipus Aegyptiacus". Thanks to the archeological researches, the original base of the obelsik was found and the scholars could identify its original location: it was in front of the East sacello of Thutmosis III. Generally, the obelisks built during the New Reign were erected in pairs inside the temples, but in this case we have just one obelisk which was placed in order to embody such a holy role that was identified with Amon-Ra himself. According to its inscriptions, it belongs to Thutmosis III and Thutmosis IV kingdom. The inscriptions were modified during the centuries: during the Amarna age both the name and the image of Amon-Ra and Karnak were deleted and were lately reintegrated during the XIX dinasty. On the pyramidion, Thutmosis III is represented in front of Amon-Ra while in the upper scene the king is making an offering to the gods on thrones. There are 12 columns of hieroglyphics which are 3 for each side. The central one is dedicated to Thutmosis III while the two lateral ones to Thutmosis IV. In the upper part of the obelisk on the East side Thutmosis III's serekh receives bread as an offer by the king, while on the South side Thutmosis IV presents the ankh to Thutmosis III's serekh. In both scenes an hawk with a double crown, which represents the monarch himself incarnated in Horus god, is on the top of the two serekh.