We celebrate Lord Jesus's resurrection vs the Romans at the time celebrating a pagan holiday.
Acts 12:1-5 KJV
Now about that time Herod the king stretched forth his hands to vex certain of the church. [2] And he killed James the brother of John with the sword. [3] And because he saw it pleased the Jews, he proceeded further to take Peter also. (Then were the days of unleavened bread.) [4] And when he had apprehended him, he put him in prison, and delivered him to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people. [5] Peter therefore was kept in prison: but prayer was made without ceasing of the church unto God for him.