"One thing I know a lot about is the legal definition of fraud," Justice Arthur Engeron said as he gaveled court into session prior to the start of opening statements.

Engoron opened the proceedings after allowing cameras in to document the scene in the courtroom: Trump, arms folded, flanked by his legal team; Engeron on the bench; and throngs of reporters and spectators in the gallery.

"I've promised to do my best despite my lame attempts at humor," Engeron said in a brief opening statement. "I take my job very seriously."

The trial is expected to last through Dec. 22, Engeron said, and suggested he would attempt to keep a low profile after today.

"For the next three months, I hope the only words I will mutter are 'Sustained,' 'Overruled,' and 'Let's take a 10-minute break,'" he said.

Opening statements are underway in former President Trump's $250 million fraud trial.

Trump is seated between his attorneys Clifford Robert, Alina Habba and Christopher Kise.

Trump and his co-defendants face a bench trial, meaning that the sole arbiter of the case is Judge Arthur Engoron instead of a jury.

Former President Trump has taken a seat in the courtroom for the start of the trial.

"The crime is against me," he told reporters outside the courtroom before he made his way inside.

He denounced the case in now-familiar terms, criticizing state Attorney General Letitia James as she sat inside the courtroom.

Trump also accused Judge Arthur Engoron of failing to account for the full value of his real estate portfolio, asserting his Mar-a-Lago estate is worth "50 to 100 times more" than the judge's decision for partial summary judgment said last week.

"We have other properties, the same thing. So he devalued everything," Trump said. "We have among the greatest properties in the world. and I have to go through this for political reasons."

Engoron decided Trump's statements of financial condition were fraudulent, but Trump said, "We have a clause in the contract that says, essentially, buyer beware."

Former President Trump, speaking to reporters on his arrival at the lower Manhattan courthouse, said the trial is a witch hunt resulting from his standing in the presidential polls.

"This is a continuation of the greatest political witch hunt of all time," he told reporters outside the courtroom.

Trump said he is innocent of the accusations and that his portfolio has a much higher value than what the attorney general alleges.

Cushman & Wakefield executive David McArdle, who was hired to appraise the value of 71 undeveloped residential units at the Trump National Golf Club in Westchester County, New York, testified that he also conducted multiple appraisals for conservation easements at the property in 2014 and 2015.

Signing a conservation easement would allow the Trump Organization to give up their development rights and treat the difference in property value as a charitable donation, according to the New York attorney general.

By giving up the right to develop the 71 residential units, McArdle found that the donation was worth $43 million, according to an April 2014 appraisal. A later appraisal McArdle conducted in 2015 landed on a similar valuation of $45.2 million.

But Trump's financial statements from those years appear to ignore the appraisals, valuing the land from the undeveloped units at $101 million, according to documents entered into evidence.

"Based on the supporting data, the only source for the increase in the number of units and profit per unit were telephone conversations with Eric Trump," the New York attorney general alleged in her complaint.

McArdle also testified that he was consulted to appraise Seven Springs, a New York estate Trump purchased for $7.5 million in 1995.

To value the property, which could be subdivided into 24 to 26 residential lots, McArdle testified that he toured the site, consulted a local expert, and spoke with Eric Trump on multiple occasions.

"He had a very high opinion of the property, which didn't surprise me," McArdle said.

His appraisal ultimately determined the total value for the lots in 2014 was $30-$50 million, McArdle said.

But the New York attorney general alleges that appraisal was ignored in Trump's 2014 financial statement, in favor of a "false and misleading" value of $161 million for a portion of the undeveloped lots.