Clive Mason, chairman of the charity, said the service on January 31, which is being held at St Mary’s Church at 7pm, is open to everyone in the community.
He said: “It will be a wonderful service, held in accordance with Thomas Oken’s wishes.
"It will be taken by the new vicar of St Mary’s, the Reverend Canon Angus Aagaard, and I would strongly encourage people to come and enjoy the music and hymns.”
It will be followed by the traditional Oken Feast, an invitation only dinner held at the Lord Leycester Hospital.
The charity makes significant grants every year to local charitable organisations and groups looking after people in Warwick.
Organisations range from the Homestart Charity for pre-natal mothers through to end-of-life care with the Myton Hospice at Home service.
Clive added: “These are two of the nine major partners we work with.
"The others being The Parenting Project, MIND, Citizens Advice, Safeline, Warwickshire College Group, Warwick Schools Foundation and Warwickshire Care Services at Woodside Care Village.”
The charity also owns and administers almshouses for the benefit of Warwick residents in need, which are located in Castle Hill and Bowling Green Street.
Thomas Oken was a wealthy merchant who survived the turbulent reigns of Henry VIII and Elizabeth I.
He was a public-spirited man who left much of his fortune to the town, including almshouses. Thomas Oken lived in Warwick during the reigns of Henry VII, Henry VIII, Edward VI, Mary I and Elizabeth I, a period of great religious change with all the social upheaval that this brought in its wake.
A mercer, who made a comfortable fortune, he devoted his talents to the service of his town and his fellow citizens. He was also heavily involved in local government and of deep religious conviction.
He was the last master of the Guild of Holy Trinity and St George, which was dissolved in 1546.
Between Michaelmas 1544 and May 15 1545, the date of the grant of the municipal charter to Warwick, he conducted the difficult negotiations with Henry VIII’s commissioners which secured for the people of Warwick a substantial part of the church and guild endowments, thereby preventing the worst effects of subsequent legislation by the Crown.
He was one of the principal burgesses named in the charter and was bailiff from 1557 from 1558 remaining a member of the corporation until his death on July 29 1573.
In his will, from his personal fortune, he arranged amongst other things, for the payment of the salary of the schoolmaster, annual payments to “the poor”, the paving of certain streets, the repairing of the bridge, the wages of the herdsmen and the beadle, the repairing of the wells, and the provision of the alms houses for six people.
Such provisions as are applicable today are carried out by Oken’s Charity including the building and maintenance of the almshouses.
He also provided for the spending of £1 annually on a feast which, perhaps, he meant to be continuance of the guild feast, preceded as that had been by a service at St. Mary’s.
The tradition is continued on the last Friday in January each year.
Nicholas Eyffler was a German immigrant from Osnabruck in West Phalia. He was born in about 1512, and settled in London probably for economic reasons rather than religious persecution.
He is believed to have come to Warwick under the patronage of Sir Thomas Lucy who was building Charlecote and supplied glass both for Lucy and for the Earl of Leicester at Kenilworth Castle.
He carried on a very successful business as a glazier at a time when glass for windows was becoming increasingly common. He became a denizen of this country (not quite a naturalised English man) in March 1562 and lived first in or near the market place and later in two houses in Jury Street.
By his will Eyffler instructed that on a close on the Back Hills (now Castle Hill) two timber framed barns should be converted and extended into four almshouses.
When the great fire of Warwick destroyed three of the almshouses belonging to Oken’s Charity in Pebble Lane, that Charity built six additional almshouses for twelve people in need in 1696 on the southern end of the almshouses at Castle Hill.
In 1996, 390 years after the rebuilding of the Castle Hill Alms houses, the charity’s Trustees carried on the proud tradition by opening the newly built Guild Cottages in Bowling Green Street.