54 years ago - Percival Sheldrake is born the son of the Earl of Wordenshire.
41 years ago - 13-year-old Percival's parents die in a plane crash.
9 years ago - 45-year-old Percival is killed by Spring-heeled Jack.
The original Knight and Squire are a pleasant throwback to a simpler era of Pre-Crisis comics. There were several "Batmen of other countries" comics out there, Knight & Squire just happen to be the ones that have had a cool modern continuity presence. As it happens, the idea that Cyril is actually Percival's son gives him a better motivation for having a teenage sidekick than Batman ever had.
In an effort to give Percival a little more narrative purpose, we gave his life a little more definition, creating the idea that he was the squire to the Shining Knight, and suggesting that he retired after the death of his wife. It was only after the fact that we discovered that we DIDN'T invent that idea, that it was actually retroactively added in regular continuity as well. Still, even if we didn't actually think of it, it's a really good idea, because it creates a source for Percival's original choice to become Knight, creating a connection between these modern characters and actual Arthurian legend.