Terra Classic is a decentralized, open-source blockchain protocol using proof-of-stake consensus. The network is the predecessor of Terra 2, with Luna Classic (LUNC) as the main currency on the network. Terra Classic was essentially an algorithmic stablecoin project, which failed in May 2022, with the UST Classic depeg.
On May 25th, 2022, Terra Classic users passed governance proposal 1623, which outlined the genesis of the new Terra chain.