Back in 2013, the Bengals had both Geno Atkins and Carlos Dunlap entering the final year of the their rookie contracts. Both players had established themselves as the two best on the defensive line, and it was the top priority for the team to sign both to new deals before they became free agents.
That summer, Atkins and Dunlap both agreed to five-year contract extensions that have kept them side by side and destroying offensive linemen ever since. They were modest deals at the time, and salary cap inflation diminished them even more as the years went on.