Answer:
Robert Recorde.
Explanation:
Robert Recorde was a Welsh known for vast knowledge and experience in the field of mathematics and physics. He was born in Tenby, Pembrokeshire, Wales during the Medieval period (c. 1512).
Robert Recorde was famously known for his work in the field of mathematics and most especially, the invention of the equal to (=) sign. He introduced it in his book titled "The Whetstone of Witte."
Hence, Robert Recorde was the first english mathematician who first used the modern symbol of equality in 1557.