A fine birds eye plan of Mainz on the River Rhine has a key to twenty eight places on the map. Matthaus Merian began publishing the ‘Theatrum Europaeum’ in 1633, it was not finished until 1738 by which time 21 volumes had been issued including some 20,000 pages of text, 720 maps, plans, views and other engravings and nearly 700 portraits. Shirley (2004) G.Werd 1a no. 85 & G.Meri 1a.