meaning

[user_gary]

I sat on my suitcase as the Swiss train carried me to a meeting I'd dreamed of for two decades. At the end of the journey waited Anne Frank's father, Otto, with whom I had corresponded since I was fourteen.

What does `corresponded' mean in this sentence?

Please explain it.

[Tdol]

Exchanged letters.

[user_gary]

Exchanged letters.

Thank you Tdol.

So I guess,
I had corresponded since I was fourteen = I used to write letter to Otto and in return they write letter. But this process occurred only after when I reached fourteen.

Am I right?

[Noego]

I had corresponded since I was fourteen = I used to write letter to Otto and in return they write letter. But this process occurred only after when I reached fourteen.

Yes, you got the idea.