First Definitive Description of Typhus
The label "typhus" describes several bacterial diseases (but not typhoid) characterized by a high fever of 104 degrees or more, joint pain and a dull red rash around the middle of the body. It is passed by lice, rodent fleas, ticks and mites. The various kingdoms of Spain, have joined to kick the Muslims of Granada off of the peninsula. The Muslims are maintaining a losing defensive position as they have been cut off from the sea and their supply lines. An epidemic of typhus hits the Spaniards as they maintain the Siege. The Spanish forces have lost 3,000 soldiers in action and 17,000 to disease. Typhus has been in Europe for hundreds of years but the description of the disease during the Siege of Granada allows a definitive identification by medical historians.      
Plus and Minus Sign: Math Made Simple and Complex
The plus and minus signs have been used in many applications before this time. For example: barrels that are empty are painted with a minus sign and are changed to a plus sign when they are full. However, the plus and minus signs are first used in print this year. Johannes Widmann publishes a textbook for understanding mercantile accounting using the minus and plus to refer to a deficit or surplus. The plus and minus will not be used for addition and subtraction until 1518 and they won't be introduced to England until 1557 along with the equal sign.   
This Year in Wikipedia
Year 1489, Wikipedia.
- * The asterisk in the section header indicates that it was read on the podcast.
- Granada War - Wikipedia (2014). Retrieved on 21 December 2014.
- The Historical Impact of Epidemic Typhus (PDF) (2007). Retrieved on 21 December 2014.
- Typhus: History - Wikipedia (2014). Retrieved on 21 December 2014.
- The History of Typhus - eHow. eHow.com (2014). Retrieved on 21 December 2014. “The Civil War was America's deadliest war in terms of American soldiers killed, but [...] prisoners in Northern camps did not seem to contract the disease as readily as their European cousins. Some scientists hypothesize that differences in North America's climate or indigenous louse might account for this anomaly.”
- Epidemic typhus - Wikipedia (2014). Retrieved on 21 December 2014.
- 7 Worst Killer Plagues in history (worst diseases, epidemics in history). Oddee.com (October 15, 2007). Retrieved on 21 December 2014. “The first description of typhus was probably given in 1083 at a convent near Salerno, Italy. Before a vaccine was developed in World War II, typhus was a devastating disease for humans and has been responsible for a number of epidemics throughout history.”
- Massive DDT Spraying in San Antonio Texas. YouTube (2014). Retrieved on 21 December 2014.
- Boards Of Canada Beware the Friendly stranger & DDT spraying on children. YouTube (2014). Retrieved on 21 December 2014.
- Viktor Emil Frankl. Man's Search for Meaning. Pocket Books. ISBN 067166736X. Retrieved on 21 December 2014.
- The birth of symbols. courses.educ.ubc.ca (September 2, 2007). Retrieved on 18 December 2014. “The + and - symbols first appeared in print in Mercantile Arithmetic or Behende und hüpsche Rechenung auff allen Kauffmanschafft, by Johannes Widmann , published in Leipzig in 1489. However, they referred not to addition or subtraction or to positive or negative numbers, but to surpluses and deficits in business problems (Cajori).”
- Plus and minus signs - Wikipedia (2014). Retrieved on 18 December 2014.
- Johannes Widmann - Wikipedia (2014). Retrieved on 21 December 2014.