I use the term "Israelites" because there is a significant school of thought which holds that we didn't really become "Jews" until the Covenant at Sinai.
The ritual itself, at least as practiced today, dates back about 1000 years or so, so it's actually a rather recent addition to our history. Still, it's by far my favorite "Chag" (holiday). This year, as most, we will host seders both nights, with a great (and different) mix of folks at both.
Chag Pesach Sameyach!
(PS Click here for a detailed and interesting deconstruction of so-called "Christian Seders")