People in York are being invited to make "a present to the past" and help preserve part of the city's heritage.
It is hoped the Hall can raise £5,000 by the end of the year
The Barley Hall is a recreation of a merchant's home from the time of the wars of the roses.
Lord Mayor of York, Councillor Janet Greenwood, will formally launch its Christmas appeal on Monday, which intends to ensure its future survival.
Organisers said tourism has been badly hit in 2005. The appeal aims to raise at least £5,000 by the end of the year.
The hall has been run by an independent charitable trust since 1997.
It offers visitors a "hands-on" chance to see what everyday life was like in medieval times.
Its Christmas programme for 2005 includes the St Nicolas Fayre Medieval Market and Christmas Candlelit Evenings.