Cryptographer Aram Jivanyan of Firo (formerly ZCoin) initially developed Lelantus as a new protocol for a confidential exchange of value.
The core principles of Lelantus describe the related proofs placing a UTXO set into a shielded pool while the anonymity set accumulates. The UTXO set leaves the shielded pool as a "new" UTXO set equally the exact total value as UTXO set initially submitted.
Beam combined Lelantus with Mimblewimble to create a hybrid LelantusMW protocol. This hybrid protocol resolves the issue of linkability, which in some instances could allow an active attack to establish a link between wallets (though not to determine identities or values of the transactions).