Northampton Borough Council plans to award £600,000 to restore 850-year-old Delapre Abbey to help secure future investment.
The Grade II listed building - and the site of the Battle of Northampton in 1460 - needs work estimated at £15m.
The council said it hoped this initial funding, proposed in its draft budget, would encourage other investors.
"We want it to be an established part of the local heritage trail," Councillor David Perkins said.
"We are making this investment to show that we are serious about the Abbey's future but this is a long term project.
"We want this investment to act as a signal to other organisations that we want to work with them to safeguard this important piece of our heritage and put the Abbey on the map as a place to visit."
The council's cabinet will consider the proposals in its draft budget on Wednesday.