Jerónimo de Ayanz y Beaumont (1553 – 23 March 1613 AD) was a Spanish soldier, painter, astronomer, musician and inventor.

He pioneered the use and design of the steam engine, as well as mining ventilation systems, improved scientific instrumentation, developed windmills and new types of furnaces for metallurgical, industrial, military, and even domestic operations.

He invented a diving bell, patented an immersion suit tested before the court of Felipe III in Pisuerga, on August 2, 1602, and designed a submarine.

[1] He made the Spanish Road, from Milan to Namur, together with his companions from the tercio under the command of Lope de Figueroa, in the record time of 32 days, in the middle of winter, to go to Flanders at the call of the Duke of Alba.

He participated in the battle of Gembloux, in 1578, and in the assault on the city of Zierikzee he carried out one of his legendary feats when, badly wounded, he continued to fight until he got rid of his attackers.

In 1582, under the orders of the Marquis of Santa Cruz, he boarded the ships that headed for the Azores participated in the Battle of Vila Franca do Campo.