You will receive this quest rigth after completing "The Reeve of Wincestre" quest. After analyzing the evidence Goodwin will tell you who The Gallows is - it's reeve Selwyn.
Eliminate the first of the Order targets.
Choking the Gallows
Quest stages of Choking the Gallows
1. Reach the market
Go to the market, which is located in the northern part of the city. When you get there, you will witness another execution led by Selwyn.
2. Assassinate the Gallows
After executing the first prisoner, Selwyn will still be standing for some time on the platform where the execution is taking place. So if you are fast enough you can climb up the columns and air assassinate him there. When the execution is over, Selwyn and his soldiers will start walking around the market and its surroundings.
When you finish him, this quest will end and you will receive the next one.
