Why did the confederates defend peterburg so fiercely?

The Confederates defended Petersburg fiercely because it was a vital supply center for the Confederate capital of Richmond, Virginia. Its railroads and roads were crucial for transporting troops and resources. Additionally, losing Petersburg would have severely compromised the Confederate position in the region, making it easier for Union forces to capture Richmond. The prolonged siege also aimed to buy time for the Confederate army to regroup and strengthen their defenses.