Greek contributions to Islamic world scholarship throughout the Hellenistic world, and Greek mathematics merged with Egyptian and Babylonian mathematics to give rise to a Hellenistic mathematics. The most important centre of learning during this period was Alexandria in Egypt, which attracted scholars from across the Hellenistic world, mostly Greek and Egyptian, but also Jewish, Persian, Phoenician scholars. Most of the mathematical texts written in Greek have been found in Greece, Egypt, Asia Minor, Mesopotamia, and Sicily. Byzantine science was essentially classical science. Therefore, Byzantine science was in every period closely connected with ancient-pagan philosophy, and metaphysics. Despite some opposition to pagan learning, many of the
Ancient Greek verbs three tenses are used, and they distinguish aspect only, not time: The optative mood likewise uses these three tenses, but there is also a future optative, used mainly to report indirectly what would be a future indicative in direct speech. Ancient Greek has no perfect progressive or past perfect progressive. Thus, the meaning "he has been doing" is typically expressed with the present tense, and "he had been doing (earlier)" is expressed with the imperfect tense: For further information on the endings, see Ancient Greek grammar (tables). Dictionaries of Ancient Greek usually give six principal parts for any verb. For