Westlake, Nathaniel

Nathaniel Hubert John Westlake (1833–1921) was not only a fine painter and stained glass designer, but also a fine scholar of the history of stained glass. His most well-known publication being A History of Design in Painted Glass. His career as a stained glass designer had two distinct phases. The first early-Gothic inspired phase, of which the Worcester Cathedral window highlighted below is an example, peaked in 1864-65. This was followed by a more pictorial style, as demonstrated by the east window of the Spring Chapel at Lavenham, illustrated opposite.
Sources:
Angels & Icons: Pre-Raphaelite Stained Glass 1850-1870 by William Waters (Seraphim Press Ltd, 2012)
Stained Glass Marks and Monograms. Complied by Joyce little (London: National Association of Decorative and Fine Art Societies, 2002)
Victorian Stained Glass by Martin Harrison (London : Barrie & Jenkins, 1980)