Leonel Power (also spelled Lionel, Lyonel, Leonellus, Leonelle; Polbero), c. 1380–1445, was an English composer of the early Renaissance. Along with John Dunstaple he was a dominant figure of 15th-ce
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x99a339cba64a95c3b9a6f1964ebd7ca5d01be91ef6c512622ad59a4d2e141763. Chain 2 (Bitcoin): anchored in block 954342 (2026-06-19T03:22:39Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/8ec7e1f6-69f3-4b88-8c4e-018301dd9629.json and https://artists.proofprofile.net/proofs/artist/8ec7e1f6-69f3-4b88-8c4e-018301dd9629.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Ars britannica. Old Hall Manuscript, Madrigals & Lute Songs