The brother of Michael IV the Paphlagonian, Stephen, was originally a caulker before he was made admiral of the fleet. His son succeeded Michael IV as Michael V (and as lover of the former's wife). Michael IV himself was a moneylender and counterfeiter, and he came into prominence in the court by virtue of his brother John, who was a courtier in charge of the women's quarters of the royal palace.
Ah, I see. I thought perhaps it was a slang term I was unfamiliar with. It's much more amusing this way. Thank you.