Question VII. (marg.) What number of day from the Egyptian departure was it, on which the arrival at Sinai [took place]?

This is, of the questions set above, the other on which they must needs disagree who disagree about the day of the third month — so much so that, for that cause, St. Jerome (on Hosea 3) wrote [that] it was the 45th day, [but] in the Epistle to Fabiola the 47th. But before judgment can be passed, three [things] are to be settled. The first: what kind of months were then in use? For that they were lunar — which are wont to be alternately full and hollow — is the opinion of very many, and especially of the Jews (on Exodus 12; in the Seder at the cited place; and in their calendars), and likewise of Abulensis, of Rupert (book 3 On the Trinity, ch. 41), of Bellarmine, and of Rabanus (at the cited places). But there are not lacking [those] who think they were solar, and indeed equal — that is, triakonthēmeroi [of thirty days], each of 30 days — and, as it seems, Arias [Montano] (in [his] book On the Times). The second is: if the months were lunar, was the month Nisan full or hollow? That it [was] full — that is, of 30 days — the Seder establishes (at the cited place), and the Jews’ present-day calendars; and therefore [that] the following month, Iyyar, [was] hollow, that is, of 29 days; the third, Sivan, again full; and so on thereafter. But Rupert (book 3 On the Trinity, ch. 41) makes that first one hollow, and the second full. The third: whether, in this reckoning, the very day of the departure is to be taken, or the day of its arrival to be excluded. Cajetan and Ribera (at the cited place) advise excluding [the arrival]. Of the first, I am pleased to subscribe to the common opinion — although from Genesis ch. 7 I think it certain [it] is gathered [that] both the years and the months, in the time of the Flood, were solar; nor do I know when this reckoning was changed. For Moses (Exodus 12) changed only some order of the months, not the number of days in them — although not even the order [was] changed by him: but [that] the first was always the spring [month] Nisan, Thomas Lydiat contends (book On the Various Forms of Years, ch. 2, p. 15). Of the second I likewise assent [that] the first of the months was full — although for making up the same number it matters nothing whether either [month] was whole or defective. Of the third, let either be done, it matters not, provided it be explained. Yet the ancients seem rather, in their reckonings, to have excluded the day of departure and included [that] of arrival. The arrival at Sinai was therefore, from the Egyptian exodus, the 47th day — according to the lunar reckoning [here] laid down, and with the day of the departure itself excluded and [that] of the arrival included. But it will be allowed to explain St. Augustine and some others by these [things] which I have said, rather than to accuse [them] as though ignorant of arithmetic. For St. Augustine (at the cited places), in order to find Pentecost [as] the 50th day, when he takes 17 [16] days from the first month, thirty from the second, three from the third, was of the opinion which embraces solar months. And therefore either those [writers] were to be refuted in Bellarmine (at the cited place), or his reckoning [is] not to be blamed. And so of Lipomanus in Ribera. All who use lunar months, and make the first day of the month the [day] on which the Israelites reached Sinai, are otherwise wont to number the day from the exodus [as] the 45th. From those five [there] follows the third little question — but which, in the order of all [the questions], is the eighth.