When you want to see when you and a friend -- or two mutual friends -- first became Facebook friends, the Friendship page is all you need. The Friendship page displays any information Facebook has about your relationship with the other person, including when you became Facebook friends, if you're related and any Life Events you've shared together. To see when you became friends, start by viewing your friend's profile.
Seeing a Friendship With You
Looking up when you became Facebook friends with someone is really only one step beyond looking at a friend's profile. In fact, the Friendship page is actually accessed from your friend's profile page.
Type your friend's name into the search bar and select her from the list. People on your friends list with the typed name appear first, but non-friends with the same name also appear in the results. Be sure you choose the right one.
Click the ... button on your friend's profile, and select See Friendship. This menu also has the Block and Report buttons, used to block contact from that friend and report inappropriate or abusive behavior, respectively.
Check just under the Friendship page's cover image. There's a box containing information about your friendship, including when you became Facebook friends.
Seeing a Friendship Between Two Others
To see a friendship between two people on your friend's list, the process starts out the same as above. Once on the Friendship page, however, there are a couple more quick steps to follow.
Click More from the Friendship page with one of the two friends you want to look up.
Select a pair of friends from the listings in the Browse Friends window. Alternatively, if the two friends you want to look at aren't listed, type their names in the text fields and click See Friendship.
Check just under the Friendship page's cover image. There's a box containing information about the friendship between the two people you chose, including when they first became Facebook friends.
If you select two people who aren't Facebook friends with one another, no information displays.