I'm not completely sure I follow what you mean by the term "waterproofs", I haven't heard that term before, but when I look it up, I find references to rain-gear.

I know of a few major waterproofing methods used with clothing prior to the spread of rubber technology.

oilskin or oilcloth was fabric, such as sailcloth treated with a drying oil, namely boiled linseed oil, which is linseed oil that has been heated in the presence of lead oxides.

Waxed cotton was cotton fabric, again, such as sailcloth, saturated with beeswax, and later paraffin wax.

tarring was a method of waterproofing fabric using pitch, a highly viscous product produced by distilling resinous wood. Tarring wasn't appropriate for most worn fabrics, because they don't flex well. But I know that it was used in waterproofing woven straw hats. Some military hats, such as the type worn by grenadiers would be tarred.

Leather, by default was not particularly waterproof, though there were methods of treating it to make it more waterproof. Again these basically relied on oils and waxes. We've got plenty of historic recipies for shoe polish that would've aided in waterproofing leather. Keep in mind that most lower level sailors would not be able to afford leather goods.

Documents would be kept in furniture, and depending on the era, various wood-finishes could be used for waterproofing, wax, shellac (secretion from the lac bug), lacquer (Urushiol resin from certain Asian trees), Japanning (a mixture of linseed oil and other stuff to form a type of paint), or tempera paints (protein based paint).

As far as the earliest records of these waterproofing efforts, I'm afraid that's beyond me. Anyway, I hope this helps!