American football fans never thought they would see the day - the head of the National Football League standing shoulder to shoulder with Donald Trump in the Oval Office. Trump has frequently traded blows with the NFL since he first became US president in 2017, but he and America's most popular sports league have been sparring partners for more than 40 years. Trump's 'feud' with the NFL has involved him testifying against the league and failing, on multiple occasions, to buy a team. It may even have propelled him to the presidency. When NFL commissioner Roger Goodell joined Trump in May to announce the NFL Draft coming to Washington DC for the first time, it seemed Trump had finally made friends with arguably his oldest foe. Well, maybe not. With this season set to conclude with Super Bowl 60 on Sunday, BBC Sport examines Trump's long and complicated relationship with the NFL and why it could be set for another twist.

**Lawsuit fails to force league merger**
Already a real-estate magnate by that point, Trump viewed owning an American football team as a means of building his brand. After attempting to acquire an NFL franchise, a 37-year-old Trump bought the New Jersey Generals in September 1983. They were founding members of the USFL, which started in the spring of 1983 so did not clash with the NFL. The new league managed to lure top players from the NFL and the college game. The Generals improved during their two seasons under Trump but lost in the first round of the play-offs in both 1984 and 1985. However, Trump made his intentions clear from the outset. He wanted to go directly against the NFL.

**Did failed Bills bid lead to presidential run?**
Trump had already attempted to buy the Baltimore Colts before the NFL franchise relocated to Indianapolis in 1984. He then turned down the chance to buy the Dallas Cowboys for $50m in 1984, instead purchasing the Generals for $9m. After the USFL's demise, Trump pulled out of discussions in 1988 to buy the New England Patriots. He focused on other enterprises, becoming a reality TV star until the Buffalo Bills were put up for sale in 2014. Trump claims he bid $1bn in cash but Terry Pegula bought the Bills for $1.4bn. That bidding process was mentioned during a fraud trial, and Trump's swollen asset claims were scrutinized. He has made statements implying that a failed bid for the Bills spurred his successful presidential campaign.

**Trump and the anthem debate**
During Trump's first presidential run, NFL quarterback Colin Kaepernick began his knee protests during the national anthem. Trump was vocal against the protests, urging fans to boycott games and pushing for player discipline. Goodell reacted to Trump's comments, stating that they demonstrated a lack of respect for the league. Trump later claimed he would love to see Kaepernick return to the NFL, as the league struggled with the anthem issue.

**Added intrigue around White House visits**
Traditionally, championship-winning teams visit the White House, but this has garnered greater attention under Trump due to political objections from players. Trump revoked an invitation to the Philadelphia Eagles after many players said they would not attend; lesser attendance has characterized subsequent visits by the Kansas City Chiefs and others. Trump's relationship with the NFL continues to evolve, with the potential for more history as he remains intricately connected to both the sport and politics.