If you say something is one in the eye for someone, it means that something is a big disappointment or a defeat for them - but you are pleased about their disappointment.
I got the job! That's one in the eye for John – I've never liked him and I was sure he would get the position. Ha!
Our winning the championship was one in the eye for our rival team – they are always boasting about their skills.
If you see eye to eye with someone, it means you agree with them. If you don't see eye to eye, you disagree.
I like my new boss: we see eye to eye on how to run the department.
The letter in this photo was written by a sailor who worked on board H.M.S Mars. It was written to his mother eight days after the battle of Trafalgar, describing his involvement in it. It's been valued at £800.