Dvořák composed his 13th string quartet in 1895, and it was performed for the first time in Prague in 1896. It is numbered opus 106, but there is an issue with the numbering of Dvořáks works: the opus numbers are not consistent, for all kinds of reasons.
In some cases Dvořáks publishers wanted to promote new work by giving it a higher opus number, suggesting that the composer was already quite advanced. In some cases Dvořák himself numbered a work lower to evade a contractual obligation. This way he was able to sell it to a different publisher. Sometimes totally different pieces got the same opus number. Opus number 12 has been used five times! Pieces were also numbered according to publication, not in order of composition. Especially this has led to a very confusing numbering of his symphonies.
An attempt to fix the matter was done in 1960 by the publication of the Burghauser catalogue. This might look like the final solution, but most programs don’t use it. This might have to do with historical continuity with earlier scores and programs.