1485: First outbreaks of Richmond's Fever, as it will be known. 
Richard III secures a victory at the Battle of Bosworth Field, with the death of Lancastrian claimant Henry Tudor.
This victory humbles Joan the Pious of Portugal, his fiancee, who had foreseen his death (and therefore agreed to marry him). She consents, and marries Richard on Christmas Eve at Westminster Abbey. Richard's main threat (in his eyes), Elizabeth of York, is married off to Manuel de Beja, Joan's cousin. 
1486: Christova Coromba approaches the court of King Richard, requesting funding for an expedition to Asia - west-wards. Richard agrees tentatively.
Queen Joan gives birth to Prince William.
1487: The first major wave of Richmond's strikes England and Wales, cutting down swathes.
The Beaufort Plot - Lord Stanley and Margaret Beaufort are caught plotting to overthrow the King, which is, of course, treason. Both get the chop.
1488: Duke Francis of Brittany suggests a new marriag