How far back does the concept of a “bold” typeface variant go

Question

What I'd like to know is where in history the idea of having a bold variant of a typeface came about.

I suspect that back in Garamond/Caslon's time there would not have been any bold version of their type, even though modern Garamond and Caslon fonts tend to include bold variants. But I have failed to find out whether this is true or when having a bold variant in typography (for the purpose of emphasis within text) came into being.

I know that giving emphasis with a thicker stroke goes all the way back to hand-lettering days, but haven't heard if this was ever true for the first few centuries of type.

Wikipedia's otherwise great History of Western Typography article has failed me here.

Answer 1

As KMSTR states, the idea of a "bold" typeface has its own channel of history. A blackletter in contrast to a Roman font would certainly appear bold, and chunky lettering goes back much further than either of those styles.

But in checking out this thread, the consensus seems to be that Clarendon is the first bold typeface that was made to complement a regular Roman face:

For the record, the Clarendon type of the Besley foundry is indeed the first type actually designed as a ‘related bold’ – that is, made to harmonize in design and align with the roman types it was set with. It was registered in Britain in 1845 under the new Ornamental Designs Act of 1842.

Follow the link and find that post; there's a picture of it in action. Good stuff.

Answer 2

According to this and this, bold typeface developed historically different from roman and italic. Emphasis (variance in blackness) was was achieved by letter-spacing. To actually achieve "bold", one would have to replace fonts. So maybe your research should focus on mixing typefaces.