The siege of Sardis was the last decisive conflict after the Battle of Thymbra, which was fought between the forces of Croesus of Lydia and Cyrus the Great, when Cyrus followed Croesus to his city, laid siege to it for 14 days and captured it.
Remains of the acropolis of Sardis, where Croesus was finally captured
Defeat of Croesus at the Battle of Thymbra, 546 BC
Inside the citadel of Sardis
The siege of Sardis, 19th-century engraving
The Battle of Thymbra was the decisive battle in the war between Croesus of the Lydian Kingdom and Cyrus the Great of the Achaemenid Empire. Cyrus, after he had pursued Croesus into Lydia after the drawn Battle of Pteria, met the remains of Croesus' partially-disbanded army in battle on the plain north of Sardis in December 547 BC. Croesus' army was about twice as large and had been reinforced with many new men, but Cyrus still utterly defeated it. That proved to be decisive, and after the 14-day Siege of Sardis, the city and possibly its king fell, and Lydia was conquered by the Persians.
Defeat of Croesus at the Battle of Thymbra, 546 BC
The Battle of Thymbra took place below the citadel of Sardis (center), and the Lydians then retreated for the Siege of Sardis (547 BC).