Abela was born in Valletta to Marco Abela and Benarda Vella[1] whose great great grandfather was Barone di Pietra Lunga and whose ancestors ruled Malta on more than one occasion and were part of the royal family of Spain.
He became Auditor of Grand Master Antoine de Paule, Chaplain and finally Vice Chancellor of the Knights Hospitaller.
Gian Francesco Abela visited archaeological sites on the islands and made some valuable observations.
He appears to have been the first to note that the ancient temple of Hercules was to be identified with the remains on the hill at Tas-Silġ rather than those of Borġ in-Nadur.
At Tas-Silġ he observed foundations and courses of stones ‘ben lavorate e messe insieme,’ and in support of his identification he recorded the discovery of ‘medaglie, pezzi di statue d’idoletti, e d’altre cose, minimi avanzi di quella vana gentilità e falsa religione, quivi ritrovate sotto il Magistero del Principe Wignacourt, mentre alcuni nell’istesso luogo cavando, scioccamente pensavano far acquisto di ricco tesoro.’[2] In the early 17th century Abela converted his house at Marsa to a historical museum, the first in Malta.