The Fraternity or Gild of Jesus at St Mary's in Baldock was founded in 1459, and the charter confirmed in 1533.

At that date it had a master, churchwardens, brethren and sisters, and found a priest who helped the parson of the church in his duties.

At the inquiry of 1548 William Tybie was the brotherhood priest, and he assisted the parson of Baldock in serving his cure.

Byrd is remembered for giving Charles I a drink of wine from this chalice when he passed through Baldock, en route from Newmarket to London under the escort of Cornet George Joyce in June 1647.

The 19th century rectory beside the church, built in 1871 and known today as 'Butterfield House', was designed by the noted eccesiastical architect William Butterfield.

The church is built of flint rubble with stone dressings, while the tower is coated with Roman cement.

There are traces visible externally on the east and north walls of windows probably dating from the early part of the 13th century.

The north-west angle stair turret and the floor of the parvise have been removed, and the porch is now open to the roof.

The statue of the Virgin Mary with Child on the north wall was given to the church in memory of the Very Rev.

The statue, by Sir William Reid Dick, had been presented to Baillie on his retirement from Windsor.

[3] The lych gate was built in 1871 at the same time as the new rectory, which was designed by noted architect William Butterfield.

The east end of the chancel is from the original church on this site and is late 12th century, but the remainder of the chancel, the north chapel (now the vestry), the nave, north and south aisles, west tower, and probably the lower part of the south porch were built about 1330.

The eastern and earlier portion of the chancel has an east window of five lights; under this window on the outside is a 14th-century niche with a trefoiled head, having a rebated edge, and the remains of iron hinges The late 14th century chancel screen (or rood screen), which is in the same line with those of the chapels, is a fine one in carved oak of three bays, and two half bays at the north and south ends.

At the top of the nave in front of the chancel screen is laid a stone slab in memory of Reginald de Argentein (died 1307), believed to be a Knight Templar and who was responsible for rebuilding the church.

[12] Outside the vestry (originally the north chapel) is a Purbeck marble coffin lid of the 13th century, with a cross in relief.

On the north wall are two, one with shrouded figures of a man and his wife, of c.1520, the other an inscription to Margaret Benet, dated 1587.

The chancel has a modern east window of five lights, containing fragments of coloured glass at the top, probably of early 15th-century date.

The stained glass at the eastern end dates to 1849 and depicts Jesus Christ in the centre, with the Four Evangelists - Matthew, Mark, Luke and John.

These windows are unique as they were re-glazed with the proceeds from the sale of covered coat hangers made and sold by Mrs Dorothy Arbury in the 1960s; this act is commemorated by the miniature coat hangers round a cross in the 'Coathanger Window' in the north aisle beside the vestry and dedicated to the memory of Mrs Arbury.

[13] The church has a peal of eight bells: (1), (2), (3), (4), (6) and (7) by Taylor of Loughborough in 1882; (5), with inscription 'Miles Graye made me, 1650'; and (8) 'Laudo Deum verum plebem voco, convococlerum defunctos ploro nuptus colo festa docoro.

The working parts of the present church clock were made by Messrs. Potts & Sons, of Leeds.

There are references in the churchwardens' accounts dated 1711 and again in 1819, where The Vestry Meeting authorised the sum of £55 for repairs to the clock and chimes.