"Recent" contact?

I need help understanding something regarding my iPhone and email. I recently tried to forward an email to a friend, and when I typed a letter, an old contact that I hadn't talked to in over two years showed up as a "recent contact". I have not contacted this person with the email account on my phone, and I never contacted the person via my new phone (number). Can anyone explain why/how that happened?

iphone 6, 10.0.2