| Clue | Source | Date |
|---|---|---|
| 556, to Cato | Eugene Sheffer | 07 Oct 2024 |
| Nero's 556 | Eugene Sheffer | 18 Mar 2024 |
| Nero's 556 | Eugene Sheffer | 10 Feb 2022 |
| Nero's 556 | Eugene Sheffer | 08 Jul 2019 |
| Mid sixth-century year | Newsday | 28 Oct 2018 |
| Mid sixth-century year | ||
| Nero's 556 | ||
| Mid sixth-century year | ||
| Mid-sixth century date | ||
| Mid-sixth century date | ||
| 556, to Cato | ||
| 556 | ||
| Mid 6th century date | ||
| 556, to Caesar | ||
| Half of MCXII |