Background
Isidore of Miletus was born c. 6th century in Miletus, Ancient Greece.
Interior panorama of the Hagia Sophia, the patriarchal basilica designed by Isidore.
Ἰσίδωρος ὁ Μιλήσιος
architect mathematician scientist
Isidore of Miletus was born c. 6th century in Miletus, Ancient Greece.
Isidore was a student of the famous mathematician Proclus.
Isidore was associated with Anthemius of Tralles in the construction of the church of Hagia Sophia at Constantinople. The church begun by Constantine was destroyed in the Nika sedition on January 15, 532. Justinian immediately ordered a new church to be built on the same site, and it was begun the next month. It is commonly held that Anthemius died in or about 534 when Isidore was left in sole charge, but this must be regarded as unproved. The church was dedicated on December 27, 537.
In the astonishing space of five years, Anthemius and Isidore erected one of the largest, most ingenious, and most beautiful buildings of all time. The ground plan is a rectangle measuring seventy-seven by seventy-one meters, but the interior presents the appearance of a basilica terminating in an apse, flanked by aisles and galleries, and surmounted by a dome greater than any ecclesiastical dome ever built. The dome rests upon four great arches springing from four huge piers; the pendentives between the arches were at that time a novel device.
As in the church of Saints Sergius and Bacchus in the same city, the stresses of the central dome are shared by half domes to the west and east, and the general similarity of plan has led to conjectures that the same architects built the earlier church. The dome nevertheless exerted a greater outward thrust on the piers supporting it than was safe, and when it had to be reconstructed after an earthquake twenty years later it was made six meters higher; but in general the applied mathematics of the architects have proved equal to the exacting demands of fourteen centuries. The decoration of the building was worthy of its artifice; the empire was ransacked to adorn it with gold, silver, mosaics, fine marbles, and rich hangings. Its ambo excited particular admiration.
Anthemius and Isidore were consulted by Justinian when the fortifications at Daras in Mesopotamia were damaged by floods; but on this occasion, the advice of Chryses, the engineer in charge, was preferred.
Isidore probably died before 558, for when a section of the dome and other parts of Hagia Sophia were destroyed by an earthquake at the end of the previous year, it was his nephew, called Isidorus the Younger, who carried out the restoration. Essentially what is extant is the church of Anthemius and Isidore, as repaired by the latter’s nephew and patched after no fewer than thirty subsequent earthquakes, in addition to the ordinary ravages of time.
Isidore was a mathematician of some repute as well as an architect. Notes at the end of Eutocius’ commentaries on Books I and II of Archimedes’ On the Sphere and the Cylinder and Measurement of the Circle indicate that Isidore edited these commentaries. The first such note reads, “The commentary of Eutocius of Ascalon on the first of the books of Archimedes On the Sphere and the Cylinder, the edition revised by Isidore of Miletus, the engineer, our teacher”; and, mutatis mutandis, the other two are identical. It was formerly supposed on the strength of these notes that Eutocius was a pupil of Isidorus; but other considerations make this impossible, and it is now agreed that the three notes must be interpolations by a pupil of Isidorus. A similar note added to Eutocius’ second solution to the problem of finding two mean proportionals - “The parabola is traced by the diabetes invented by Isidorus of Miletus, the engineer, our teacher, having been described by him in his commentary on Hero’s book On Vaultings” - must also be regarded as an interpolation by a pupil of Isidorus. The nature of the instrument invented by Isidorus can only be guessed - the Greek word normally means “compass” - and nothing is otherwise known about Hero’s book or Isidorus’ commentary on it.
The third section of the so-called Book XV of Euclid’s Elements shows how to determine the angle of inclination (dihedral angle) between the faces meeting in any edge of any one of the five regular solids. The procedure begins with construction of an isosceles triangle with a vertical angle equal to the angle of inclination. Rules are given for drawing these isosceles triangles, and the rules are attributed to “Isidore our great teacher.” It may therefore be presumed that at least the third section of the book was written by one of his pupils.
It is evident that Isidore had a school, and it would appear to have been in this school that Archimedes’ On the Sphere and the Cylinder and Measurement of the Circle - in which Eutocius had revived interest through his commentaries - were translated from their original Doric into the vernacular, with a number of changes designed to make them more easily understood by beginners. It is evident from a comparison of Eutocius’ quotations with the text of extant manuscripts that the text of these treatises which Eutocius had before him differed in many respects from that which we have today, and the changes in the manuscripts must, therefore, have been made later than Eutocius.
Isidore was undoubtedly a genius mathematician and possessed extraordinary engineering skills.
Isidore had a nephew, Isidore the Younger, who introduced the new dome design that can be viewed in the Hagia Sophia in present-day Istanbul, Turkey.