The role of a football manager is often precarious. Fans and owners demand results - and quickly.
After Ipswich Town sacked Paul Hurst following just one win in 15 matches in charge, his replacement turned more than a few heads.
Paul Lambert, who led the Tractor Boys' rivals Norwich City to two successive promotions as manager, was handed the job of turning around Ipswich's poor form.
But what about the other bosses who went on to manage their previous club's bitter rivals?
We've picked 15 managers who crossed the divide. Can you name them in our quiz below?
Can you name these managers who have taken charge of two or more rival clubs?