Rope in be in a dominating position over others this conjures up a picture of a cock lording it over a group of hens (a roost) but it is more likely to be a relatively modern corruption of the older 'rule the roast', a reference to the joint of meat that would be carved by the master of the house or be the principal dish at the table he presided over (ruled).
And here's another truth!
The “dot” over the letter “i” is called a tittle.