Four are the elements from which the rainbow takes its colours
Quadricolor enim est . ex omnibus elementis in se rapit species. De celo enim trahit igneum colorem . de aquis purpureum . de aere album de terris collegit nigrum.
For it [the rainbow] is of four colours, and takes its appearance from all of the elements into itself. From the sky it draws the fiery colour, from the waters purple, from the air white, and from the earth it gathers black.
Four are the woods from which Christ’s cross was built
Four are the gospelists who wrote down the life of Christ
The Cologne Gospels: London, British Library Harley MS 2820
Four are the horsemen at the world’s end
Four are the years of this blog: thank you to all my readers!