Donald Trump split Monday with campaign manager Corey Lewandowski, in arguably the highest-profile staff shake-up of the 2016 season – a move that comes after a tumultuous period for the billionaire businessman, and just weeks before he is set to claim the Republican presidential nomination at the GOP convention.

A Trump senior campaign aide confirmed to Fox News on Monday morning that Lewandowski is no longer with the campaign.

It's unclear what specifically led to the decision. The departure of one of Trump's most senior and loyal advisers follows what was widely seen as a rough patch for the campaign.

"Generosity. That was my first mistake."
"Experience must be our only guide; reason may mislead us."
"Instagram is Twitter for people who can't read."