We don’t know if the Last Supper was a Seder, but that is what tradition holds, and it certainly would have made sense: a big dinner among Jews on a fine Spring evening. Also, three of the four Gospels state that it was a Seder, so there’s that.
This year, the stars (actually the sun and the moon) have aligned to give us the first night of Passover on Good Friday. If it fell one day earlier, then it would be an exact re-enaction of what may have happened in (we think) 33 C.E.: on Thursday, Jesus had Seder (the second Seder, like the second day of Rosh Hashanah, is an invention of the diaspora: Jesus wouldn’t have observed one); the following day, the crucifixion, Good Friday.
It made me wonder if in recent years this confluence ever had occurred: Erev Pesach falling on the Thursday night before Good Friday. But going back three decades, not only has the first Seder never been on this date—it’s never been on any Thursday. I’m hoping some more learned commenter can enlighten us as to why.
Oh well. We’ll always have Maundy Thursday, that most awesomely named of holidays. And by “we,” I obviously don’t mean “we.”
Update: That didn’t take long. Via Twitter, here are the days of the week on which the first day of Passover can fall. Friday is not one of them, which means that a first Seder can’t fall on a Thursday night.
Related: Jesus’ Final Passover [Slate]