The Life and Legacy Of Astronomer Abraham Zacuto

A perk  of joining  Jewish heritage tours in Portugal is learning about the influencial Jews who made their mark in the country’s history. One such individual is Abraham Zacuto.


Abraham Zacuto
Abraham Zacuto (Hebrew: אברהם זכות‎)  was a Portuguese astronomer, astrologer, mathematician, rabbi and historian who served as Royal Astronomer in the 15th century to King John II of Portugal. The crater Zagut on the Moon is named after him.
Zacuto was born in Salamanca, Spain in August 12 1452. He may have studied and taught astronomy at the University of Salamanca. He later was a teacher of astronomy at the universities of Zaragoza and then Cartagena. He was versed in Jewish Law, and was rabbi of his community.

With the expulsion of the Jews from Spain in 1492, Zacuto took refuge in Lisbon, Portugal. Already famous in academic circles, he was invited to court and nominated Royal Astronomer and Historian by King John II of Portugal, a position which he held until the early reign of Manuel I. He was consulted by the king on the possibility of a sea route to India, a project which he supported and encouraged.

 Zacuto would be one of the few who managed to flee Portugal during the forced conversions and prohibitions of departure that Manuel I enacted nin order to keep the Jews in Portugal as nominal Christians for foreign policy reasons. He fled first to Tunis and later moved to Jerusalem. He died probably in 1515 in Jerusalem, however, other reports indicate his final home was in Damascus and the death occurred in 1520.

In a similar vein to other giants of the Jewish faith, such as Saadia, Maimonides and the Vilna Gaon, he followed the extremely old Jewish custom (believed to have begun in Babylon) of being buried as close to Jerusalem as possible. Zacuto had established his wish to make his death pilgrimage at a Passover gathering.

Zacuto’s Contributions

Zacuto developed a new type of astrolabe specialized for practical determination of latitude while at sea. This was in contrast to earlier multipurpose devices intended for use ashore. Abraham Zacuto's principal claim to fame is the great astronomical treatise written while he was in Salamanca. The treatise is named Ha-ḥibbur ha-gadol (Hebrew: החיבור הגדול‎) ("The Great Book") and was written from 1470 to 1478. It was composed of 65 detailed astronomical tables (ephemerides), with radix set in year 1473 and the meridian at Salamanca, charting the positions of the Sun, Moon and five planets.

Almanach Perpetuum
The calculations were based on the Alfonsine Tables and the works of earlier astronomers (notably of the 14th-century Majorcan school). Zacuto set out the data in a simple "almanac" format, with the positions of a planet easily interpolated between entries, making it quite easy to use.

Already in 1497, Vasco da Gama took Zacuto's tables and the astrolabe with him on the maiden trip to India. It would to be used by Portuguese ships thereafter to reach far destinations such as Brazil. Vasco da Gama and his crew underwent thorough briefing and preparation by Zacuto, in addition to learning to use the new instruments which he had developed for their trip before setting on the voyage to India.

Prior to that, Zacuto had again improved on the existing astronomical tables, mostly those prepared under King Alphonso X of Castille. Christopher Columbus had used Zacuto's tables as well. There is a story telling that on one of his voyages, when attacked by the natives, Columbus noted that Zacuto had predicted an eclipse for that day, and used this information to threaten the natives and convince them that he could extinguish the Sun and Moon and deprive them of all light. Zacuto's work saved the Columbus‘  life and that of his crew.

In 1504, while in Tunisia, Abraham Zacuto wrote a history of the Jewish people, Sefer yuḥasin (Hebrew: ספר יוחסין‎), since the Creation of the World until 1500, and several other astronomical/astrological treatises. The History was greatly respected and was reprinted in Cracow in 1581, at Amsterdam in 1717, and at Königsberg in 1857. A complete uncensored edition was published by Filipowski in London at 1857.

Annotations in Hebrew to chapter five of Sefer Yuhasin, were published by Yoel Lieberman in 2001 in a masters thesis called "A Record of Medieval Sages In Sefer Yuhasin of Rabbi Abraham Zacut". The book was translated into English and published in 2005 by the Zacuto foundation founded by Dr. Vladimir Rozenblit, a 20th generation direct descendant of Zacuto.

Salamanca, Spain
For more lessons on historical Jewish figures in Portugal, feel free to join one of the many kosher tours that will happily guide you around the sights and sounds of Portugal.

What is Tu Bi’Shvat?

Jewish tradition has variety of holidays derived from the ancient agricultural calendar and historical events of ancient Israel. We modern Jews use our holidays to take a vacation, perhaps even a kosher tour to Jewish heritage sites. Sometimes we take them for granted and do not meditate on their importance to Judaism.

One of the chagim, considered by many as a minor holiday, is in fact absolutely extraordinary. It neither celebrates divine intervention nor any historical events. It doesn't even celebrate the work of human hands. It is a celebration of nature, a celebration of the coexistence of people and trees.

Tu Bi’Shvat  - Planting Tree
Tu Bi’Shvat, the “Fifteenth of Shevat”, is also known as the “New Year of Trees”.
The great prophets and interpreters of the Torah worked to turn Israelites away from the pagan tree cult which was quite widespread in the Middle East. One might expect that our scholars would had refused any signs of respect for the trees as a sort of idolatry.

But it is not.

In the Bereshit, there is a story of Avraham Avinu planting a tamarisk near Beer Sheva, or that he sometimes would spend time in a “sacred grove”. Also other Hebrew heroes were judged, enthroned, taught or buried under significant trees.

Biblical writers did not remove these memories from the text and did not need to censor it or be apologetic. There is evidence that the trees are not the property of the pagan sanctuaries and cults, but that they have a place among the Am Yisrael.

For more than 2,000 years, the New Year of Trees was a celebration of the coming of Spring and the waking up of nature in the Promised Land. This holiday commemorates the crops that people feed on – and which are also the work of their hands, the fruit of the trees, and the gifts of the earth, the first-fruits of which were brought to the temple. It is also the celebration of all the trees and bushes that grow in the wild, those who have no other task than to celebrate the Divine name and to be home and food for birds and a source of shade for all.



In the holiday of Tu Bi’Shvat, Judaism goes beyond the framework of culture, civilization, religion and the human community. It recalls the importance and beauty of non-human creation. Trees are a memory of the Garden of Eden, where, according to the Ramban, they were cultivated by the Creator himself as His own property.

HaShem did not let Adam care for them, but He Himself planted, cared for them, and gave them the privilege to grow and to bear fruit forever:

"Their roots will not die in the earth, their trunk will not die in dirt. They do not need anyone to nurture and prune them. If they needed care, who would trim them after people would be taken away? It means that HaShem himself planted them, they are the trimming, pruning and work of His Own Hands, and so it will be forever."

In modern times, interest in trees and nature is particularly relevant, because our selfish and indifferent treatment of creation could lead to the destruction of the world. Bereshit recalls the failure of man in the Garden of Eden. We are currently facing very similar dangers. Just as the first people have lost their paradise, we can lose our livelihood due to our greed and pride.
The New Year of Trees, which this year falls on January 31th (the Erev on January 30th), reminds us all of our responsibility for our planet.

The Old Burg Of Bamberg

Bamberg, known in Old Germanic as Babenberg, after the famous Babenberg royal dynasty of Germany, is an ancient town situated in the fertile valley between the two shoulders of the Regnitz river, a tributary of the Main in Bavaria,  south-east of Germany.

Bamberg City

History

The first mention of Bamberg as a castle owned by the Babenberg family dates back to 902. But it is assumed that there was an older, perhaps Celtic, settlement on the hilltop of Altenburg – the “Old Castle“. At the time of the Great Migration, the Slavs pushed the Germanic tribes out and controlled the area. Remnants of their primitive stone deity statues were found in the 19th century. Later, however, the countryside was again populated by Germanic tribes.

In 903, The Babenbergs fought with the Franconian Conrads over the territory and the town later became part of the Royal Crown. In 973, Emperor Otto II gave Bamberg to his cousin Henry the Quarrelsome, Duke of Bavaria. His son, the German King, and later Holy Roman Emperor Henry II. founded the bishopric in Bavaria in 1007. At the same time, he began to build the Kaiserpfalz – the “royal stronghold“ and the magnificent Dome (1004). It is assumed that he chose Bamberg to be his seat of power.

The bishopric originally answered directly to the Pope. Later, the bishops became the lords of the city, and there was no change during the bourgeois uprisings (the largest was in 1435). The city did not gain freedom. Initially, a Bamberg developed a long-distance trade relationship with both Rhineland and Bohemia. But in the 13th century, Nuremberg was at the top.


Bamberg - Obere Mühlbrücke

Bamberg town hall from opposite bridge

During the Thirty Years' War, the city remained on the side of the Catholic League and was occupied by Swedish troops in 1631-1648. Just before, during 1625-1631, a series of brutal witch trials took place in and around the city, for which Bamberg’s bishop Johann Georg of Dornheim was responsible. The exact number of victims is unknown, but according to estimates and incomplete documents it could have been over a thousand that were executed or tortured—most of them women.

After the Thirty Years War, Bamberg went through its cultural pinnacle. Under the leadership of Bishops of the Schönborn family, extensive baroque reconstruction of the city took place in the first half of the 18th century. The four Dientzenhofer brothers were hired by the Bishops as their court builders and left a large imprint behind.

In 1801, Bamberg became part of Bavaria to compensate for the loss of the Rhine Palatinate following the French-Austrian peace treaty in Lunéville. In 1802, the city was occupied by Napoleon’s soldiers, and the bishop became subordinate to them. His office was temporarily canceled. The incorporation of the Bamberg territory into the Bavarian Kingdom was confirmed by the Viennese Congress in 1814-1815. In 1817, the Bavarian bishopric was promoted to Archbishopric. The ancient bishoprics of Würzburg, Speyer and Eichstätte were incorporated into the new archdiocese.

A Look Into The Town

Bamberg, also called Franconian Rome, is situated on seven hills and in the valley between the shoulders of the River Regnitz. The charming cottages on the banks of the river, once-inhabited by fishermen, are collectively called "Little Venice" (Klein Venedig). In the historic burghers‘ district, the houses are packed and the city is interwoven with a network of winding streets.

 Bamberg also has a world rarity in the form of an originally Gothic town hall building, standing on a bridge in the middle of the river. The Town Hall was rebuilt in Baroque style in the middle of the 18th century. Near the Old Town Hall is the ring-shaped Geyerswörth castle with its tower.


Bamberg Old Medieval Synagogue

The bishop's part of the town (Bischofsstadt) is dominated by a Romanesque-Gothic style church with four slender towers and an interior with beautiful Gothic decoration. This  is the third church built from 1211-1237, as the previous two were burned. There is also a sculpture from the first half of the 13th century (the so-called Bamberger Reiter), representing the ideal medieval knight on his horse that is world-famous. It is believed that it could be the King of Hungary, St. Stephen I, the brother-in-law of Emperor Henry II – or Henry II himself.

The interior of the cathedral is also remarkable by having two choirs with altars. The west one is dedicated to St. John the Baptist. Peter and the remains of Pope Clement II. It is the only papal grave to the north of the Alps. There is also an eastern chorus with an altar of St. George and in front of the tomb lies the remains of the only canonized king, the Emperor Henry II and his wife Kunhut. In the eastern crypt there is a sarcophagus with the coffin of another German king, Conrad III, who died in Bamberg.

Bamberg New Synagogue


In the square in front of the dome opposite the Old Hofchaltung from the 16th century, the Prince-Bishop Lothar Franz von Schönborn erected a magnificent Baroque New Residence (Neue Residenz) at the turn of the 17th and 18th centuries. The Bamberg branch of the state gallery has its headquarters today in the premises of the New Residence.  Visitors can admire the works of the old masters and the castle halls decorated with beautiful stuccoes. In 1647, an academy was founded in Bamberg, which was abolished in 1803 and later restored - today, the Otto-Friedrich University in Bamberg.

The Bamberg Jews

It is hardly possible to summarize the history of the Jews in Bamberg – which is as old as the local history itself – in a moment, although this may sometimes happen with terms like "Rintfleisch" and "Holocaust". But Jewish presence in Bamberg is definitely more than that!

It is not known when the first Jews in Bamberg settled. It is theorized that they, together with Roman legions, came to southern Germany as merchants. But we can safely assume that since the beginning of the diocese in Bamberg, the Jews already settled there. The diocese celebrated its millennium in 2007, so we could say that Jewish presence in the city is more than a thousnad years old.

Except for a few years when Jews were actually expelled from Bamberg, e.g. in 1478, and apart from the great catastrophe that is the Shoah, Jews have always lived in Bamberg. The prince-bishops, as spiritual and temporal lords, were always well paid by the Bamberg Jewish community – until secularization in the early 19th century (1803). However this “local custom“ was so deeply-rooted that this princely gift of money was expected from the Jews of Bamberg even after that.

A constituted Jewish community in Bamberg is mentioned for the first time in the 2nd half of the 12th century. In the area of Pfahlplätzchen, a small community with a synagogue was recorded. The synagogue was confiscated in 1478 by the then prince-bishop and demolished. In its place, a Marienkapelle church was built and the Jews were expelled from the city. Later they were allowed to come back, but they had to pay immense taxes for their stay in the city as well as for the right to stay, the so-called "Gedinckten Zins".

 Later, in the upper Kesslergasse, the today’s Hellergasse, a new second prayer hall was established. Finally in the Generalsgasse from the 17th century a new synagogue was built, and was rebuilt in 1853. However, the conversion was so varied that the synagogue resembled a new building and thus also the fourth synagogue had to be built. Finally, in 1910, the large, richly decorated grand – fifth – synagogue in the Herzog-Max-Straße was consecrated. This one was destroyed in 1938 during the Kristallnacht.




The prewar community ceased to exist and most of the original members were murdered by the Nazis. However, this did not mean the ultimate end of Bamberg’s Jewry. The community was reestablished after the war; it grew very slowly but steadily, uniting a colorful mix: the local Jews who survived the holocaust and stayed, and new Jewish immigrants, who arrived as immigrants mostly from Eastern Europe and the Soviet Union. But also there were also members of the dispatched US Army units who joined.

Today's synagogue is the seventh in the history of Bamberg. It opened in 2007, on the one-thousand-years anniversary of the existence of the Jewish community. The building houses not only the synagogue, but also a communal center, Jewish school and a kosher canteen that serves the several-hundred-strong community of Bamberg. The community is still growing to this day. The Jewish community of Bamberg is one of the best examples of rebirth of Jewish life in nowadays Germany. For Jewish travelers who are interested in knowing more about the history of the Jews in Bamberg, they will definitely learn a lot from Jewish heritage tours in the area.

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