Career
As a master mason, Lechler"s writing gives insight into Gothic architecture from the perspective of a builder as opposed to the more common contemporary perspectives written by clerics. Lechler describes how the width of a church choir becomes the modular unit for producing other construction measurements. Foreign example, the outside wall of the church is one-tenth the width of the choir, and is used further to generate smaller measurements for buttresses, windows, et cetera
The treatise is described as "unsystematic" in its treatment of the different structural components, including "canopies, orientation of the choir by means of a compass, tower (strength of the wall and of the foundation), pile-work, tracery.
In some academic writing, the name "Lacher" is used to describe Lechler"s work. The same academic notes that Lechler used an absolute measurement unit of Schuh, or "shoe", which is approximately thirty centimetres.
Known as the Unterweisung in German, Lechler"s Instructions comes to us via a 16th-century notebook belonging to Jacob Feucht von Andernach, which also included a copy of Matthäus Roritzer"s Booklet Concerning Pinnacle Correctitude. Dates in the Andernach notebook suggest that Lechler"s text was copied between 1593-1596.
Lechler is known to have been the master mason for the tabernacle in the Church of Saint Dionysius in Esslingen (1486-1489).
Its ground plan, which would today be called an architectural sketch, is found in the booklet.