Science Department

Restoring the burial plaque of Jean de Brébeuf

(This article is based mainly on information found on the website of the Canadian Conservation Institute….¹)

In 1639, French Jesuits established Sainte-Marie Among the Hurons near present-clay Midland in Ontario on the south shore of Georgian Bay. This settlement, actually a fort enclosed by wooden stakes, served as a retreat for Jesuit missionaries and a refuge for Christian Huron Indians from the area. At its height, one-fifth of the European population in New France were based here.² Jean de Brébeuf was one of the leading Jesuits at Sainte-Marie.

Traditional Indian rivalry led to the killing of Brébeuf by the Iroquois in 1649. His remains were recovered and buried inside the walls of Sainte Marie. But later that year, given the hostility of the Iroquois, the French abandoned the fort and burned it down. In the middle of the last century, archeological excavations unearthed a lead plaque noting Brebéuf’s death. The plaque and its inscription are shown here.

The plaque, which went on display in the reconstructed fort in 1971, recently began to corrode rapidly and was sent to the Canadian Conservation Institute (CCI) for restoration. Experts there ascertained that the plaque was largely lead and that the corrosion products included basic lead carbonate, lead acetate and possibly lead formate, all common corrosion products of lead in the presence of organic acid vapours. As stated on the website:

"Basic lead carbonate can protect the lead underneath if it has formed in a homogeneous layer that is strongly adherent. However, in the presence of small amounts of organic acid vapours, basic lead carbonate forms as a loose, non-adherent powder. The organic acid vapours [released perhaps by the wood of the display cases] stimulate corrosion and act as a catalyst. Once active corrosion has started, it can continue for a prolonged period in the presence of carbon dioxide alone, the organic acid being regenerated and largely reused as the porous corrosion layer thickens."

Three restorative techniques were considered. Two of these, electrolytic consolidative reduction and consolidative reduction in sodium dithionate, convert the basic load carbonate back to lead metal and must be used if the inscription is present only in the corrosion layer. However, the inscription in the Brébeuf plaque extends into the lead metal, so it was decided to dissolve away part of the corrosion layer so as to reveal the inscription more clearly. The CCI website¹ explains:

"We chose DTPA [diethylenetriamine pentaacetic acid], since it is already used to treat lead objects in the CCI Archeology section. The plaque was immersed in a bath of DTPA and almost immediately  it began to react, with small bubbles forming on the surface as the lead carbonate became soluble, releasing carbon dioxide. The uneven discoloration on the surface began to disappear, being replaced by an overall lighter grey colouring. At the same time, the black material highlighting the lettering became more apparent. After about one and a half hours in DTPA,  the appearance of the plaque had greatly improved: the lettering was easier to read, and the colour was more even. The lead carbonate layer was much thinner, and the metallic lead was exposed at the corners and in several spots on the surface. We stopped the treatment at this point, because the appearance was better with part of the corrosion layer left in place, rather than completely stripped. Partial cleaning may also have allowed the lead acetates or formates to dissolve."

"The plaque was washed in running tap water and in changes of boiled distilled water to remove chemical residues. It was rinsed through acetone, dried and immediately placed in a desiccator containing dried silica gel and activated charcoal."

The restored burial plaque of Jean de Brébeuf, ~9.4 x 5.2 cm.

The inscription:  P[ère] Jean de Brébeuf / bruslé par les Iroquois, / le 17 mars l’an / 1649. (Translation: Father Jean de Brebéuf, burned [at the stake] by the Iroquois, on the 17^th of March 1649.

The Sainte-Marie Among the Hurons site was excavated by archeologists in the 1940s and 1950s, and reconstruction commenced in the 1960s. A personal note: In August 1962, my wife and I spent a night in Midland. At breakfast we asked the restaurant owner about sites to see in the area. He mentioned Sainte-Marie and directed us to the local bookstore where we bought a book⁴ recently published by two of the archeologists. Using this book as a guide we wandered around the site which, at that time, was mostly mud and grass. Several areas outlined building locations. Using the book’s drawings as a rough guide, we got an impression of the nature of the site.

Today reconstruction is nearly complete A self conducted tour, starling with a video that gives historical background, is a most interesting way to spend a couple of hours, Across the street from Sainte-Marie is the Martyrs’ Shrine, a Roman Catholic church built in 1925, and visited by Pope John Paul II in 1984.³

For more information surf the net. Some useful websites are:

1. www.presentation.gc.ca/gallery/plaque_e.asp

2. http://www.entrenet.com/~groedmed/saintemarie/smah.html

3. http://www.wyandot.org/pope.htm. Contains Pope John Paul II address given at Martyrs' Shrine outside Midland, Ontario on September 15, 

   1984.

4. Wilfrid Jury and Elsie McLeod Jury, Sainte-Marie Among the Hurons, Oxford University Press, 1954.

5.  www.wyandot.org/wn_stmar.htm. This is accessible from the site of the Wyandot Nation of Kansas,

     www.wyandot.org.

     When the Wendat (Huron) natives dispersed, some of them  settled in Kansas.