The Gregorian calendar was a reform of the Julian calendar instituted in 1582 by Pope Gregory XIII, after whom the calendar was named, by papal bull Inter gravissimas dated 24 February 1582. The motivation for the adjustment was to bring the date for the celebration of Easter to the time of year in which it was celebrated when it was introduced by the early Church. Although a recommendation of the First Council of Nicaea in 325 specified that all Christians should celebrate Easter on the same day, it took almost five centuries before virtually all Christians achieved that objective by adopting the rules of the Church of Alexandria (see Easter for the issues which arose).
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What calendar was started in the fifteenth century?
Ah, so.. unanswerable

In English, the term referring to a person first appears in the mid 14th century as Catelaner, followed in the 15th century as Catellain (from French). It is attested a language name since at least 1652. Catalan can be pronounced as /ˈkætəlæn/, /kætəˈlæn/ or /ˈkætələn/.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is a Catalan person called in the 15th century?
Ah, so.. Catellain

The pricing of risk refers to the incremental compensation required by investors for taking on additional risk, which may be measured by interest rates or fees. Several scholars have argued that a lack of transparency about banks' risk exposures prevented markets from correctly pricing risk before the crisis, enabled the mortgage market to grow larger than it otherwise would have, and made the financial crisis far more disruptive than it would have been if risk levels had been disclosed in a straightforward, readily understandable format.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the incremental compensation required by investors for taking on addition risk called?
Ah, so..
pricing of risk