Story highlights The rally will take place on the same day as the annual White House correspondents' dinner

The 100 days measure is linked to President Franklin Roosevelt, who signed 15 major pieces of legislation early in his presidency

(CNN) President Donald Trump tweeted Saturday that he will mark his 100th day in office on April 29 by "holding a BIG rally in Pennsylvania."

Next Saturday night I will be holding a BIG rally in Pennsylvania. Look forward to it! — Donald J. Trump (@realDonaldTrump) April 22, 2017

The rally will take place on the same day as the annual White House correspondents' dinner, which the President has declined to attend.

The announcement comes just a day after Trump tweeted about the "ridiculous standard" of the 100-day construct for measuring the achievements of a new administration.

No matter how much I accomplish during the ridiculous standard of the first 100 days, & it has been a lot (including S.C.), media will kill! — Donald J. Trump (@realDonaldTrump) April 21, 2017

The 100 days measure is linked to President Franklin Roosevelt, who signed 15 major pieces of legislation early in his presidency; the time frame is when a president's power and influence with Congress is likely the greatest.

Trump himself talked repeatedly about his first 100 days when he was campaigning last year. It was part of his stump speech in the final week of the campaign -- he asked his crowds in Minnesota, Florida, Pennsylvania, North Carolina and elsewhere to "imagine what we can accomplish in the first 100 days of a Trump administration."

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