The crooked man is reputed to be the Scottish General Sir Alexander Leslie, who signed a covenant securing religious and political freedom for Scotland. The “crooked stile” in the poem was the alliance between the parliaments of England and Scotland or the border between the two, depending on the source. “They all lived together in a little crooked house” refers to the fact that the English and Scots had at last come to an agreement, despite the continuing great animosity between the two peoples, who nonetheless had to live with each other due to their common border.
The great recoinage around 1696 led to sixpence coins that were made of very thin silver and were easily bent, becoming “crooked”. The Crooked Man rhyme is featured as a possessed/haunted object in The Conjuring 2. The title was used for the 1960 Norman Wisdom film, There Was a Crooked Man, as a pun for a ‘crooked’ politician.