Salisbury Cathedral and Chichester Cathedral, 1402 to 1861) and fallen down; instead, Salisbury became the tallest church spire in the country on the collapse at Lincoln in 1549. The large supporting pillars at the corners of the spire are seen to bend inwards under the stress. The addition of reinforcing tie-beams above the crossing, designed by Christopher Wren in 1668, halted further deformation. The beams were hidden by a false ceiling, installed below the lantern stage of the tower. Significant changes to the cathedral were made by the architect James Wyatt in 1790, including replacement of the original rood screen and demolition
Strasbourg Cathedral together represent some of the earliest uses of architectural drawing. The work of Professor Robert O. Bork of the University of Iowa suggests that the design of the Strasbourg façade, while seeming almost random in its complexity, can be constructed using a series of rotated octagons. The north tower, completed in 1439, was the world's tallest building from 1647 (when the spire of St. Mary's church, Stralsund burnt down) until 1874 (when the tower of St. Nikolai's Church in Hamburg was completed). The planned south tower was never built and as a result, with its characteristic asymmetrical form, the cathedral