But a pressing question hangs over the entire trial: What does any of this have to do with the Trump campaign and the 2016 election, which Mueller was initially directed to investigate?
Manafort is now fighting in court charges of 18 financial crimes, including submitting false income tax returns to the IRS. A document prosecutors say was sent to a bank showed a much higher income for Manafort's company than documents Washkuhn's firm produced.
Washkuhn also testified that Manafort kept her in the dark about foreign accounts he used to pay personal expenses, which supported Mueller's claims that he withheld information from financial advisers as he cheated the Internal Revenue Service.
As late as August 2016 - the same month he resigned from the Trump campaign - Manafort was sending emails to Laporta asking her to alter a profit-and-loss statement for his company.
Ayliff and another bookkeeper who worked with Manafort, Heather Washkuhn, were the only two witnesses to testify Thursday afternoon.
The trial, in federal court in Alexandria, Virginia, is the first of Mueller's prosecutions to reach a jury.
Cindy Laporta - who knowingly filed a false 2014 tax return on behalf of Manafort - was granted immunity to testify against him in his criminal tax-evasion and bank fraud case. She said Gates told her he was handling the documentation even though he knew the loans were phony.
Ayliff described Gates as Manafort's partner and right-hand man, but when asked who was in charge in the relationship, he said, "Oh, Mr. Manafort".
She said she knowingly sent the fraudulent letter to the bank because she thought the institution would vet the document.
After a break, Laporta admitted that she went along with the plan even though she "knew it was wrong". That wasn't good enough for Gates.
It is clear to me he is very anxious about it and he wants to prevent it any way he can. Washkuhn testified that she couldn't make the change. Mr Gates pleaded guilty in February and is expected to testify against Mr Manafort, possibly next week.
Prosecutors have already relayed evidence they said showed Manafort personally directed millions of dollars in worldwide wire transfers to pay for high-end suits and more than $3 million in improvements at various houses.
"Judge, this is not an effort to prove Mr. Manafort lived lavishly", Andres said. At that time, Calk was seeking a job in the Trump campaign and administration, prosecutors said. While reports typically reflected only income that had already been collected, Manafort requested she create a document to "reflect collection of income earned in Ukr of 2.4M that is to be collected".
In his opening statement Tuesday, defense lawyer Tom Zehnle told the jury they should expect to hear how Manafort never faced a federal inquiry about his taxes, making it suspicious that prosecutors brought this case. Manafort was aware of the reported loan, which served to reduce his income, she said.
Gates will likely be asked about whether he helped his boss move money overseas and hide those accounts. Gates said he did so at Manafort's direction. She communicated with Manafort weekly or biweekly.
"I very much regret it", she told prosecutor Uzo Asonye. "He was very detail-oriented".
Prosecutors tightened the noose on Manafort for the tax evasion charges Friday during questioning with Ayliff and Laporta.
One Republican who is in frequent contact with the president, told Sherman that "the Manafort trial is spinning him into a frenzy". In his answer, Manafort said he had "NONE".
Many a government attorney has lost a corporate financial case or had a mistrial because evidence became too dense, boring or confusing for the jury to follow.