克雷莫纳的杰拉德Gerard of Cremona

克雷莫纳的杰拉德的名字常写作克雷莫纳的杰拉德，有时也写作Gerhard。在意大利接受教育后，他意识到欧洲的教育是狭隘的，于是他决定通过将阿拉伯语主要著作译成拉丁语，使欧洲学者能够获得阿拉伯科学的丰富成果。

为此，克雷莫纳的杰拉德前往西班牙的托莱多，打算学习阿拉伯语，以便能够阅读克劳狄乌斯·托勒密的AlmagestⓉ（主要论题：源自阿拉伯语“al-majisti”——希腊语“Mathematike Syntaxis”的阿拉伯语译本，后来译为拉丁语“Magna Syntaxis”），因为当时不存在拉丁语译本。尽管我们没有关于克雷莫纳的杰拉德前往西班牙日期的详细信息，但他在1144年肯定已经在那里了。

他余生的大部分时间都留在那里，尽管他似乎没有在身边聚集起一个学派，但他确实似乎得到了相当多的帮助。他可能雇用了助手，帮助他抄写和校对手稿，以及处理与他所开创的伟大翻译事业相关的其他杂务。在总共四十年的时间里，克雷莫纳的杰拉德将大约八十部著作从阿拉伯语译成拉丁语。他所翻译著作的完整列表见[1]。其中一些译作是阿拉伯语著作，另一些则是已被译成阿拉伯语的希腊语著作。然而，这些著作往往是混合性的，即它们是希腊语著作的阿拉伯语评注。

这些著作并非全都是数学著作。有些涉及一般科学，另一些涉及医学。然而，最重要的是天文学、几何学和其他数学分支方面的著作。克雷莫纳的杰拉德在档案中被提及为以下著作的译者：(i) Banu Musa兄弟的著作，(ii) 札杨尼的Tabulae Jahen（这里采用克雷莫纳的杰拉德翻译的拉丁语名称），(iii) 阿尔·奈里兹对欧几里得的Elements的评注，而这些评注本身又基于al-Hajjaj从希腊语翻译的Elements阿拉伯语译本，(iv) 塔比·伊本·库拉的著作，(v) 阿布·卡米勒的著作，以及(vi) 艾哈迈德·伊本·优素福·米斯里 ibn 艾哈迈德·伊本·优素福·米斯里关于比和比例的著作。

此外，当然，克雷莫纳的杰拉德翻译了Almagest，但对此有一个小小的谜团。我们今天所拥有的译本出现在1175年（或者至少手稿上标明了这个日期）。我们知道克雷莫纳的杰拉德前往托莱多，意图翻译AlmagestⓉ（主要论题：源自阿拉伯语“al-majisti”——希腊语“Mathematike Syntaxis”的阿拉伯语译本，后来被译为拉丁语“Magna Syntaxis”），而这样一位多产的翻译家会等到六十一岁才完成他认为最重要的任务，这似乎令人难以置信。它必定在25年前就已完成，这可能是一个修订版，或者仅仅是一个新抄本，被标注了抄写日期而非首次完成日期。

考虑到他所承担任务的规模，克雷莫纳的杰拉德除了翻译之外还能有多少时间做其他事情，这似乎很难令人相信。然而，他确实进行了公开讲座，并因此获得了学识渊博的高度声誉。

克雷莫纳的杰拉德在翻译中做出的一个决定是将阿拉伯语中表示正弦的词译为拉丁语sinus，我们的正弦函数即由此而来。有趣的是，如果克雷莫纳的杰拉德在翻译中做出了不同的决定，那么这个对所有哪怕只是短暂学习过数学的人都熟知的函数，今天就会以不同的名称而为人所知。

在5中，克雷莫纳的杰拉德的贡献被总结如下：-

由于他成果的丰富性和系统性，他对文本传统的彻底批判态度，以及他对字面意义的忠实遵循，再加上十二世纪持续不断的潮流，克雷莫纳的杰拉德的译本很快在接下来的几个世纪中获得了拉丁学者的青睐。从十三世纪初开始，中世纪大学中对阿拉伯和希腊科学与哲学兴趣的巨大高涨，其刺激在很大程度上要归功于克雷莫纳的杰拉德的工作。

Gherard of Cremona's name is often written as Gerard or sometimes Gerhard. After being educated in Italy, he realised that European education was narrow and that he decided that he would try to make the riches of Arabic science available to European scholars through Latin translations of the major works in Arabic.

For this reason Gherard went to Toledo in Spain where his intention was to learn Arabic so he could read Ptolemy's Almagest Ⓣ since no Latin translations existed at that time. Although we do not have detailed information of the date when Gherard went to Spain, he was certainly there by 1144.

He remained there for most of the rest of his life and although he does not appear to have gathered a school around him, he certainly appears to have had quite a lot of assistance. He may have employed helpers who assisted him in the copying and checking of manuscripts and other chores associated with the great translation industry that he started. In all over a period of forty years, Gherard translated around eighty works from Arabic to Latin. The complete list of works which he translated is given in [1]. Some of these translations were of Arabic works while others were of Greek works which had been translated into Arabic. Often however, the works were a mixture in the sense that they were Arabic commentaries on Greek works.

It was not the case that these works were all mathematical. Some were on science in general, others were on medicine. The most important, however, were on astronomy, geometry and other branches of mathematics. Gherard is mentioned in the archive as the translator of (i) works by the Banu Musa brothers, (ii) the Tabulae Jahen (to give them the Latin name as translated by Gherard) of al-Jayyani, (iii) al-Nayrizi's commentary on Euclid's Elements which themselves were based on al-Hajjaj's Arabic translation of the Elements from the Greek, (iv) work by Thabit ibn Qurra, (v) work by Abu Kamil, and (vi) Ahmed ibn Yusuf's work on ratio and proportion.

In addition, of course, Gherard translated the Almagest but there is a slight puzzle over this. The translation which we have today appeared in 1175 (or at least this date is stated on the manuscript). We know that Gherard went to Toledo with the intention of translating the Almagest Ⓣ, and it seems beyond belief that such a prolific translator would have waited until he was sixty-one years old before completing what he considered his most important task. It must have been completed 25 years earlier, and this may be a revised edition or simply a new copy which has been given the date of copying instead of the date of first completion.

It seems hard to believe that, given the size of the task that he undertook, Gherard would have had much time for anything other than translating. He did however give public lectures and, in so doing, gained a high reputation as a man of great learning.

One of the decisions made by Gherard in his translating was to render the Arabic word for sine into the Latin sinus, from where our sine function comes. It is interesting to realise that had Gherard made a different decision in his translation, this function, which is well-known to all who have made even a brief study of mathematics, would be known by a different name today.

In [5] Gherard's contribution is summed up as follows:-

Because of the abundance and systematic nature of his production, his thoroughly critical approach to textual tradition, and his faithful adherence to literalness, together with a steady flow of the twelfth century, Gerard's translations soon came to obtain the preference of Latin scholars through the succeeding centuries. The tremendous upsurge of interest in Arabic and Greek science and philosophy in medieval universities from the start of the thirteenth century owes its stimulation in greater part to the work of Gerard of Cremona.