The Equal Rights Amendment was passed by Congress in 1972 and submitted to the states for ratification. Congress imposed (or tried to impose?) a 7-year time limit on ratification.
There was precedent for such a time limit. Each of the 18th, 20th, 21st, and 22nd Amendments includes a section like this:
This article shall be inoperative unless it shall have been ratified as an amendment to the Constitution by the legislatures of three-fourths of the several states within seven years from the date of its submission to the states by the Congress.
The 21st says "conventions" rather than "legislatures". At least one other proposed amendment included a similar section.
But the ERA's time limit was in the resolution that introduced it, not in the amendment itself. (I believe this raises some questions about the validity of the deadline, but I'm not asking about that here.)
Apparently Martha Griffiths was the author of the resolution.
Why was the time limit written as part of the resolution rather than as part of the amendment itself, as had been done for five previous proposed amendments?