The threading is undoubtedly English. If it's a cup-and-cone (very likely if it's the original ) you need a lock ring tool and a pin spanner to remove the adjustable (non-drive side) cup. You also need a fixed cup wrench for the drive side cup.

If it's a cartridge type (probably is if it's a replacement) you need a Park BBT-2 tool.

See the Park web site for detailed directions on both types.