sentences:  He had played many times against Paolo Boi in Italy, and they were regarded as being equal in strength.Giovanni Leonardo di Bona won the first known international master tournament in the history of chess in Madrid in 1575, therefore becoming the strongest chess master of the time.After their success at the Court of Spain, Leonardo and Paolo Boi, both travelled, albeit separately, to Lisbon, where they tested their chess skill against "Il Moro", the eminent chess champion of King Don Sebastian, of Portugal.