Irrational numbers are Pi, Euler’s Number, and the Golden Ratio

How did early mathematicians discover that irrational numbers exist?
At what point did they give up and decide that the numbers to the right of the decimals would never repeat and never stop?
How far did they calculate out before making that decision … 1000 places ….10, 000 places
How many irrational numbers are there?
Can you put irrational numbers in fraction form?