Events that occurred on 13 March.
 On Earth
- 1956 - J.R.R. Tolkien receives a letter from a Sam Gamgee – from Tooting (see Letter 184).
- 1969 - Adam Tolkien is born.
 In Arda
- T.A. 2510:
- T.A. 3019:
- Frodo is stung by Shelob and subsequently captured by the Orcs of Cirith Ungol.
- The Pelennor is overrun by the enemies of Gondor.
- Faramir is brought back to Minas Tirith badly wounded.
- Aragorn arrives at Pelargir and captures the fleet.
- The Rohirrim travel towards Minas Tirith. They cross the Drúadan Forest.
- Beregond sees a strange light in the tower of Minas Tirith, being Denethor confronting Sauron.
- T.A. 3020:
- T.A. 3021: