How did Passover become connected to the Christian celebration of Easter?

The connection between Passover and Easter is rooted in the historical timing of the Crucifixion and Resurrection of Jesus, which occurred during the Jewish Passover festival.123

Early Christians initially celebrated the "Lord’s Passover" at the same time as the Jewish feast, specifically on the 14th day of the month of Nisan. This practice linked the Christian commemoration of Christ’s death and resurrection directly to the Jewish lunar calendar.452

By the middle of the 2nd century, most Christian churches shifted the celebration to the Sunday following the Jewish Passover to emphasize the Resurrection, which occurred on the first day of the week. This transition sparked the Paschal controversies, as some groups—known as Quartodecimans—continued to observe the feast on 14 Nisan regardless of the day of the week. The Council of Nicaea in 325 eventually decreed that Easter should be observed universally on a Sunday. Additionally, the term Pascha (used in Greek and Latin for Easter) is derived from the Hebrew Pesaḥ (Passover), and the tradition of the "Lamb of God" draws symbolic imagery from the Passover lamb.5432