2 Historians follow rules to help them analyze
primary sources. Some of the rules they use are:
• Every piece of evidence and every source must
be read or viewed skeptically and critically.
• Each piece of evidence and source must be
cross-checked and compared with related sources
and pieces of evidence.
—Library of Congress
These rules are designed to help historians
determine the
(1) reliability of document information
(2) popularity of a publication
(3) differences in belief systems
(4) laws of a civilization