The dating of the various components of the font matches this historical data (Previous article, ‘Historical Background‘). 
All the principal authorities (RCHM,[1] Clive Rouse,[2] NADFAS[3]), agree that the Purbeck marble stem and base are 12^th C (Clive Rouse thought late 12^th C).  They also agree that the circular platform on which it stands is formed of a ring of clunch (hard chalk) with a filling of red brick and cement that looks like it was once the base of a Norman, 12^th C, pillar. There was no font cover shown in a pencil sketch of the font made in 1819.[4]  The present octagonal, oak lid is Victorian, its shape laid down by the leaders of the Gothic Revival as representing the seven Sacraments and crucifixion.

The Purbeck marble of the stem and base is likely to have come from one of three sources – the Isle of Purbeck in Dorset, Petworth in Surrey or Bethersden in Kent.  Ready-made pieces were produced in these factories.  It is not a true marble but a hard limestone chiefly composed of fossilised fresh water snails varying in colour from creamy white, grey, light brown, green and blue.  It can take a high polish and can be darkened to a near black with varnish or oil.  The beauty of the highly polished marble was preferred to richness of design, but if left in damp conditions, over the centuries it flakes and roughens, as ours has done, and this is why Purbeck marble went out of fashion in the 14^th C.[5]

The dating of the cup-shaped bowl itself presents problems.  It is not a solid lead font, it is a stone font covered with lead.  The stone is completely concealed, inside and out, under a layer of lead, which is generally dated to the16th or 17^th C, presumably on the basis that graffiti scratched into the lead on the outside of the bowl, run from 1626 to 1776.  RCHM assumed that the bowl itself was probably 16^th or 17^th C; Pevsner declared it to be a bowl of uncertain date[6]; Clive Rouse thought that the lead was 16^th or 17^th C, possibly covering an original bowl; and NADFAS declared the bowl shape to be of the Transitional period, c.1200.

However, there is a visible clue to the age of the bowl that all these eminent authorities appear to have missed.  A church law, dating from 1236, required medieval fonts to be kept lidded and locked to prevent the theft of the holy water, highly valued for cures and for witchcraft.  The lids were required to be secured by a padlocked metal bar across the top.  The metal bar usually passed through two large iron staples set opposite eachother in the top rim of the font.  This arrangement was probably in general use before 1236, but thereafter, throughout the Middle Ages, Bishops’ visitations included a check that it had been done.[7]

This requirement ceased abruptly with the Reformation, after which belief in holy water was regarded as idolatrous.  The staples were removed, often leaving either a stump or a hole, and their presence is firm evidence of a pre-Reformation font.   We have exactly this evidence on our font.  On one side of the rim there are two 5/16 inch diameter stumps standing just proud under the lead about 2 inches apart, and directly opposite there is one corresponding sunken hole of similar size.

We can therefore be confident that we have a medieval stone bowl whose dimensions (2 ft 2 inches wide, 1 ft deep) and shape are consistent with the late 12^th C.

A particularly meticulous and reliable vicar of Penn, who had supervised the digging of a vault under the east end of the chancel in 1797, reported seeing the date 1177 on a foundation stone.[8]   This accords with:

1. Historical evidence that it was towards the end of the 12^th C when Penn became an independent parish and would therefore have needed its own font.
2. The age of the font.
3. The age of the nave walls as evidenced by the very yellow nature of the mortar.[9]
4. The age of the pair of tall, narrow windows with semi-circular heads in the north wall[10].
5. The age of the three consecration crosses.[11]

We can therefore be confident that our font is as old as the church and that both are over 800 years old.

[1] RCHM (Bucks) 1912
[2] E.Clive Rouse, a former President of the Bucks. Arch. Soc.‘, Notes on the church of Holy Trinity, Penn’ (c.1940). Unpublished, but held in the parish archive in Penn.
[3] NADFAS, Record of church furnishings (1984), compiled by the Thames Group, Bucks.
[4] British Museum Add 36359, f18.
[5] W.Norman Paul, The Local Historian, op. cit., pp.132-7.
[6] Nikolaus Pevsner, The buildings of England, Buckinghamshire (1994), p.595.
[7] J.G.Davies, op. cit., pp.70-1.
[8] British Museum, Add 9411.  Letter, dated 9 Aug 1802, from Rev. John Middleton, Vicar of Penn, to Lysons author of Magna Britannia.
[9] E. Clive Rouse, op.cit., and Record of Bucks (1953-4), 16, Pt I, ‘Notes’, p.51.
[10] These two windows were revealed, bricked in, when the exterior roughcast was removed in 1955, but can be seen in use in a pencil sketch of 1819 in the British Library, BM Add 36359, f 18.  They seem to be of the Transitional period (1145-89).
[11] E.Clive Rouse, Records of Bucks, op.cit.  He suggested that the crosses were 13^th C  on the assumption that the church had first been built in 1213.  This date was erroneously based on the earliest record of a vicar available at that time.  However, Ann Ballantyne, his former assistant is a conservator and has worked on these crosses.  She says that they have been repainted and that the original is on an island of the earliest mortar to which she has no difficulty in allowing a late 12^th C  date.