harry potter - Before Voldemort, who was the last Horcrux creator?

Horcruxes are rare (and then seven come along at once...) and only a few people know about them.

But when was the last Horcrux before Voldemort's? 50 years before him? Centuries? Millennia?

Answer

I'm going to limit this question to "among the known users of Horcrux's".

In which case the answer is: 2600 to 2800 years ago.
But... I'd say it's sufficient to say more than 2000 years ago.

The most recent Horcrux-er other than Voldemort is Herpo the Foul¹.

Depending on how loosely you want to take the description of Herpo the Foul who was said to be a wizard in "Ancient Greece", which is traditionally described to be 600 to 800 BC.

There are no other known creators of Horcrux's.
While there is only negative evidence to support this (that Herpo was the 2nd most recent user), the HP Wiki notices the same thing. So, while there's no canon, the negative evidence is generally accepted as proof.

_{1. 2007 interview}