According to reports, Apple's Steve Jobs personally contacted Samsung in July of 2010, in order to negotiate terms when Apple first suspected Samsung's Galaxy S devices were violating Apple patents. Here's a quote from the PhoneArena article with a few details,
These revelations come courtesy of Richard Lutton, who is a high-ranking director at Apple and its patent attorney. He also said that once the patent infringement talks between Apple and Samsung began, Steve ceased his involvement and left it to his legal department.

While responding to questions by Samsung's lawyer David Catterns, Mr Lutton noted that Steve Jobs's involvement was a simple courtesy call: “Samsung is an important supplier with whom we have a deep relationship. We wanted to give them a chance to do the right thing.”
Further industry intel indicates that Mr. Jobs was not directly involved in these negotiations, but was simply the "bearer of the olive-branch" to get negotiations started. Shortly after negotiations began, Samsung didn't agree with Apple's assessment of the situation, and felt that Apple was simply using their working relationship to pressure Samsung into compliance. This eventually led to the patent war that is going on now.

Source: PhoneArena