Leather samples in microcosms were divided into two analysis groups, each analysed separately to monitor differences caused by either the soil environment (group 1) or leather tannage and finishing (group 2). TS: typical soil conditions, WL: waterlogged soil conditions, LO: low oxygen soil conditions, M: microcosm ID.

	Group 1	Group 2
Remit	Assess impact of differences in soil environment	Assess impact of differences in leather manufacturing
Soil types	TS, WL and LO (wet and dry)	TS only
Soil pH	Acidic, neutral and basic	Neutral only
Leather tannage	Oak tanned	Oak-, mimosa- and chestnut-tanned
Oiling	Oiled	Oiled and unoiled
Dyeing	Undyed	Madder-, vinegaroon-, or undyed
Excavation regime	2, 4, 6 and 8 months	4 and 8 months
Other	Cold control and No sample control	Iron inclusions near leather sample