Here are some possible topics and their related books for Badge Number Two.
If you can think of something else linked to the Number TWO, or if you read a book which is not mentioned below, that is absolutely fine! Just make sure you can explain why and how your chosen book relates to this number.
Other suggestions: other creatures with two parts (e.g. centaurs, pegasus); Janus (the double headed god); fights between two great rivals (e.g. Rome vs. Carthage, Caesar vs. Pompey, Patricians vs. Populars); the Eastern and Western Roman Empires.

There are a number of famous twins in ancient history! How about a book featuring the mythological founders of Ancient Rome?
KS2: Romulus and Remus - Prof. Melissa Fitzgerald
KS3: Roman Mythology for Kids - Doyle Wellinner
KS4: The Brotherhood of the Rose - David Morrell
KS5: Mother of Rome – L. J. Trafford

The two famous genres of ancient Greek theatre! How about a book about theatre, or even reading an ancient Greek play?
KS2: Mark of the Cyclops: An Ancient Greek Mystery - Saviour Pirotta
KS3:The Story of Antigone - Ali Smith
KS4: Antigone - Jean Anouilh
KS5: Lavinia - Ursula K. Le Guin

Ancient Egypt was split into two lands: Upper and Lower Egypt. Can you find a book which mentions this?
KS2: Adventures in Ancient Egypt – Linda Bailey
KS3: Tales of Ancient Egypt – Roger Lancelyn Green
KS4: River God - Wilbur Smith
KS5: The Memoirs of Cleopatra - Margaret George

The consul was the highest elected public official in the Roman Republic. Each year two men were elected to this position.
KS2: So You Think You’ve Got It Bad? A Kid’s Life in Ancient Rome - Chae Strathie & Marisa Morea
KS3: Ancient Rome: The Rise and Fall of an Empire - Simon Baker
KS4: The Ides of March - Valerio Massimo Manfredi
KS5: SPQR: A History of Ancient Rome - Mary Beard

Artemis and Apollo were the twin children of Zeus and Leto. In Greek mythology, Apollo was the god of the sun, music, and prophecy, while his sister Artemis was the goddess of the moon and the hunt.
KS2: Artemis the Brave - Joan Holub
KS3: The Trials of Apollo - Rick Riordan
KS4: She Who Hunts: Artemis: The Goddess Who Changed the World - Carla Ionescu
KS5: Circe - Madeline Miller

There are a number of creatures in ancient mythology which are made up of two creatures. A famous example is the minotaur, a creature with the head of a bull and the body of a man!
KS2: Theseus and the Minotaur - Hugh Morden Lupton
KS3: Lost in the Labyrinth - Patrice Kindl
KS4: Bull - David Elliott
KS5: Once a Monster - Robert Dinsdale

Castor and Pollux were twin sons of the Spartan queen Leda. When mortal Castor died, his immortal brother Pollux shared his immortality with him - they became the constellation Gemini.
KS2: Simply the Quest - Maz Evans
KS3: Percy Jackson and the Olympians: The Battle of the Labyrinth - Rick Riordan
KS4: Mockingjay - Suzanne Collins
KS5: The Song of Achilles - Madeline Miller

Did you know that Sparta had two kings ruling at the same time? There are a few books that mention this...
KS2: 100 Facts: Ancient Greece - Miles Kelly
KS3: The Spartan - Caroline Dale Snedeker
KS4: Thermopylae: The Battle for the West - Ernle Bradford
KS5: Gates of Fire - Steven Pressfield