In 21st century America, we all know that New Year's Day is January 1st. But, did you know that this wasn't alway so?
From 1582 until 1751, England refused to adopt the 'new' Gregorian Calendar on the grounds that it was steeped in Roman Catholic 'superstitions' and not at all proper for a Protestant country. This resulted in almost two centuries of dual and/or contradictory dating of legal documents, governmental proclamations, newspapers, and other printed materials. Sometimes the document would follow the practice of every other European nation, including Protestant Scotland, and use January 1st as the start of each new year. Sometimes the document would follow the English practice of starting each official new year on March 25th. Sometimes the document would list both years for any date between January 1st and March 25th, as in 'January 1, 1700/01'. You can easily imagine the potential for confusion and complications this ongoing situation led to in England and its dominions and colonies.
The latest exhibit in the Williams Library Atrium illustrates this cultural anomaly of Early Modern English governance with facsimiles from books held by Georgetown Law Library's Special Collections.