When was the weak nuclear force unified with electromagnetism?

The electroweak theory was developed in the late 1960s, with key work by Steven Weinberg in 1967 and independent contributions from Abdus Salam and Sheldon Glashow. It showed that the weak nuclear force and electromagnetism are two aspects of one underlying interaction at high energies. This was a major step toward the modern Standard Model. The theory was strongly confirmed by later experiments, including the discovery of the W and Z bosons in 1983.