I've uploaded year 1421 to the TSP Wiki...
Here are a few one-liners...
In a Word: Discovery -- How does one say that the Portuguese discovered the West African coast? Actually... the word for "discover" in Portuguese means "to find by chance." I also write about the King James Bible and the word for "kill". It doesn't mean today what it meant in 1611.
Star Fleet... Exploring Strange New Worlds -- A history buff in the modern day claims that the Chinese discovered America. This is theory seems to lack sufficient proof to be credible... so naturally... they made it into a science special for TV!
Ridding the City of Injustice... and Jews -- The Jews of Vienna set themselves on fire rather than convert. A plaque commemorating the removal of injustice (meaning the Jews) will remain in the square until 2014 when it is finally removed.
In a Word: DiscoveryThe word "discovery" is tricky. How can we say "Columbus discovered America," when there are Indians on the shore staring back at him? The word "discover" comes from a Latin word meaning "to uncover." In Portuguese, descobrir means "to find by chance." For navigators of the 1400s, "discovery" means "I found a new way to look at this shoreline and I wonder how it fits in with what I already know." Unfortunately navigation at this time is hit or miss... mostly miss. For example: 200 years later when the Mayflower sets out to drop off the Pilgrims at the Virginia colony, they will miss their destination by a few hundred miles. This was considered "good navigation" for the 1600s. Thus when we say "Bob, the sailor, discovered the West African coast," we mean "Bob found something new to him and he must figure out if it is something already known to those who sent him." Nothing more. Really.   
Star Fleet... Exploring Strange New WorldsIn the modern day, a British history buff will make sensational claims that the Chinese of the Ming Dynasty made a trip to America and provide the original maps for Christopher Columbus. The Star Fleet of China is a mission of exploration, but that exploration has been limited to India, Sri Lanka, East Africa and what is the modern day Middle East. But the Ming dynasty will be pulling the fleet back soon. Fighting against the Mongols will seem more important.   
Ridding the City of Injustice... and JewsThe accusation against the Jews of Vienna is host desecration but at this point the charges are irrelevant. One way or another, the Jews will be expelled from Vienna or killed outright. The Pope has called for the Jews to be brought into the religious community, meaning... convert or die. 200 Jews have barricaded themselves in the synagogue and after three days have set the synagogue aflame rather than be taken alive. Years later a plaque will be set in the Jewish Square commemorating how the Viennese "rid the city of all injustice." It will remain in the square well into the modern day while a Holocaust Museum is built in the same square. The plaque will finally come down in 2014.       
This Year in WikipediaYear 1421, Wikipedia.
[Update (2014-Sep-7): Added "Ridding the City of Injustice... and Jews" and "This Year in Wikipedia".]