Topfhelms also called Greathelms have not been found in large quantity.
There are less than 20 examples and some of them were dug up from grounds.
This page will give people the ideas of general shape of greathelms and their transitional forms.

Please feel free to toss some information you know of

Update note
The Greathelm has been divided into 4 stages, which is suggested by
Leslie Southwick in "The Great Helm in England" Arms & Armour, Vol. 3, No. 1, Spring 2006, 5–77
Surviving Nasal helms and Kettle helms will make us better understand the general structures of The prototype helm

1.The prototype helm (1170~1190) Image
2.The first true great helm (1190~1220) Image
3.The developed true great helm (1220~1270) Image
4.The Great helm with truncated skull (1270~1300) Dargen and Bolzano Helms, The skull is tapered

14/10/09
Pot helm section has been added

14/10/08
Nasal and Kettle helm.sections have been added.
Seal section has been added to Greathelm section.


Topfhelms(updated in October 6th)

1.The prototype helm(1170~1190)

Manuscript

Statues and Arts

Germany
A Carved tympanum

Italy
Abbey of Santa Giustina,Via Giuseppe Ferrari, Padova, Italy


2.The first true great helm(1190~1220)

Seal
1195~1198 Richard I's second seal,England -----Image
1198 Robert Fitzwalter,England
1199 Guillaume, Count of Clermont in Auvergnes
1202 William de Warenne,6th Earl of Surrey
1207~1215 Robert Fitzwalter,England -----Image
1209 Hugues de Malaunai
1214 Alexander II, King of Scotland -----Image
1216 Louis of France(later Louis VIII)
1217 Ranulfus Blundeville, 6th Earl of Chester and 4th Earl of Lincoln, created Earl of Lincoln
1217 William Longspee, Earl of Salisbury
1219 Mathieu II, Lord of Montmorency


Manuscript

Statues and Arts

Aquamanila or Chess Pieces


3.The developed true great helm(1220~1270)

Effigies
UK
1.Church of St Mary the Virgin, Walkern, Hertfordshire, England
2.Church of St Leonard's Without, Kirkstead, Lincolnshire, England
3.Church of St Mary and St Martin, Blyth, Nottinghamshire, England
4.Furness Abbey, Barrow-in-Furness, Cumbria, England  (2 effigies) Link2
5.Whitworth Parish Church, Whitworth, Durham, England
6.All Saints Church, Hurworth-on-Tees, Durham, England
7.St mary's Church, Twyford, Bucks,England

Manuscript

Statues and Arts
UK
1230-40 Cathedral Green, Wells, Somerset, England: 3 Statues with Greathelms -----Image
1250.Church at Cottingham, Northamptonshire ----- Image1 Image2

France
1220-1250 musée de Cluny ----- Image

Aquamanila or Chess Pieces
US
1250 Metropolitan museum[/url](in US), Probably made in Hildesheim, Germany -----Image

UK
1.Ashmolean Museum 

German
1220~1270. Kunstgewerbemuseum -----Image

Norway
1.Kulturhistorisk museum, Link2  Link3

Denmark
1.Denmark National Museum Link1 Link2

Seal

4.The Great helm with truncated skull(1270~1300)
Survivng Examples
Germany
1.Deutsches historical museum, Dargen Greathelm Circa 1270/1280 -----Image

Sweden
1.Historiska Museet, Stockholm, Sweden, Circa 1300 ----- Image1 Image2

Italy
1. Bolzano Helm, Circa 1300 ----- Image

Effigies

Manuscript

Statues and Arts
Spain
1.Santa Maria La Real de Olite, Navarre
http://www.knight.by/books/Helms_article.pdf: Very very similar to the Dargen Greathelm.

Aquamanila or Chess Pieces

UK
1270-1300 British Museum ----- Image

Italy
1275-1299 Bargello museum in Florence ----- Image
1275-1299 medieval Museo Civico, Bologna ----- Image

Seal



Nasal helm

Kettle helm

Pot helm


Etc helm[/i][/url]

There is one from Årnäs in Västergötland, Sweden dated to 1300 roughly.

http://mis.historiska.se/mis/sok/fid.asp?fid=116708&g=1

There is some info here as well: http://www.myArmoury.com/feature_spot_ghelm.html