title: Safety pin
context: After being issued U.S. patent #6,281 on April 10, 1849,[6] Hunt sold the patent to W. R. Grace and Company for $400 (roughly $12,000 in 2018 dollars). Using that money, Hunt then paid the $15 owed to a friend and kept the remaining amount of $385 for himself. What Hunt failed to realize is that in the years to follow, W.R. Grace and Company would make millions of dollars in profits from his invention.[7][8]
question: When was the first safety pin developed?
answers: April 10, 1849