"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.

Testifying about the preparation of the Trump Organization's statements of financial condition in 2011, former Mazars USA accountant Donald Bender said Trump executives largely provided the input data for statements, in addition to dictating the standards by which the work was completed.

"We would cut and paste that information into a new worksheet," Bender said about the approach taken by Mazar after receiving new data from co-defendant Jeffrey McConney of the Trump Organization.

When asked about the compliance with the Generally Accepted Accounting Principles -- which Bender testified are the standards for accounting in the United States -- Bender repeatedly placed responsibility in the lap of the Trump organization.

"That was the Trump Organization's responsibility," Bender testified about GAAP compliance.

Bender acknowledged that he rarely questioned the inputs from the Trump Organization, and when he did, he largely dealt with McConney and executives other than Trump and his adult sons.

Repeatedly asked by the state attorney if Mazars would have issued the statements if they had known the Trump Organization included material misrepresentations in their data, Bender reiterated that Mazars would not have issued the statements.

When Judge Engoron remarked at the end of the trial day that the state would still need to present further evidence to prove that the 2011 statement was within the statute of limitations, Trump seized the statement as a partial victory.

"The last five minutes was outstanding, because the judge actually conceded that the statute of limitations … is in effect," Trump told reporters as he was leaving court.

Engoron, however, did not completely rule out the 2011 evidence during trial, instead appearing to remind counsel that they need to show the 2011 statement represents an ongoing concern that falls within the statute of limitations.

Testimony is scheduled to resume on Tuesday at 10 a.m. ET.