A charitable trust started by a prominent business family has committed £500,000 towards the costs of reburying Richard III.
The Samworth Foundation has promised to underwrite part of the expense of remodelling the cathedral to accommodate the tomb.
The foundation was launched by Sir David Samworth and his brother, John, of the Samworth Brothers food empire.
Clergy at Leicester Cathedral are seeking to raise £2.5 million to pay for the reinterment of the king next spring.
A spokesman for Sir David said the money had been pledged to the cathedral before the bones of the king were identified, but he was happy the cathedral used it as it saw fit.
Cathedral spokesman Liz Hudson said: "David Samworth has been extremely generous.
"It would be illegal to take on contractors without having the resources to pay them and David's participation has helped us enormously.
"He is very proud of Leicester."
Mayor Sir Peter Soulsby, who has agreed to commit £250,000 of city council cash to the reinterment, if required, said: "David Samworth has been very generous in his donations to the church.
"As a city we are enormously grateful to him."
Leicestershire County Council will also underwrite £250,000.
None of the underwriters will necessarily have to contribute if the cathedral can raise the money it needs through private donations.
The Diocese of Leicester has agreed to pay £500,000. Mrs Hudson said: "The money is coming in and there are a number of potential donors.
"For some people it is a very private matter but we will be looking to do a book to register all donations, from £500,000 to £10."
