Not to mention older than #ActivityPub.

Before ActivityPub and Mastodon became a mass phenomenon together, the "holy trinity" was #Diaspora, #Friendica and #Hubzilla, all connected via the Diaspora* protocol and, ironically, connectors not developed by the Diaspora* team. #StatusNet was kind of dragged in, too, but couldn't connect to Diaspora*. And after identi.ca had switched from StatusNet to Pump.io, StatusNet barely mattered anymore anyway.

That said, nobody called it "Fediverse" back then.