Final answer:
National banks were placed under central authority with the Union Congress' approval of the National Bank Acts of 1863 and 1864, and further through the creation of the Federal Reserve System by the Federal Reserve Act of 1913.
Step-by-step explanation:
Control of National Banks
The Union Congress passed legislation placing national banks under the control of a central authority, namely the Federal Reserve.
Initially, the National Bank Acts of 1863 and 1864 helped establish a national banking system and a uniform national currency, enabling federal chartering of banks and requiring them to purchase U.S. bonds.
The Federal Reserve Act of 1913 further strengthened federal oversight by creating the Federal Reserve System, which set the foundation for federal control over monetary policy, bank lending and stability in the banking system.
Later reforms, such as the Banking Act of 1935, continued to enhance federal control over the banking system, establishing a more centralized Federal Reserve with a board of governors to oversee regional banks thus affecting reserve requirements, discount rates and policy-making.