Romance in Numbers

Copyright © MCMXCVII by Paul Niquette. All rights reserved.

Roman numerals are still being used... 
I On cornerstones and gravestones,
II For pagination at the beginning of a book,
III On watches and clock-faces,
IV To represent the charge on an ion in chemistry,
V For expressing the luminosity class of stars,
VI To represent the order of discovery of satellites,
VII For expressing coagulation factors in physiology,
VIII To designate the height of mountains in surveying,
IX For specifying generations in a pedigree,
X To enumerate the items in a list.
What year in history required the largest 
number of Roman numerals to express?