Abel Seyler

Abel Seyler was born in 1730 in Liestal outside Basel in Switzerland. He was the son of the Reformed clergyman, Dr.theol. Abel Seyler (Seiler) (the elder) (1684–1767), who was parish priest of Frenkendorf-Munzach in Liestal from 1714 to 1763, and Anna Katharina Burckhardt (1694–1773). He grew up in a learned and pious Reformed family and was descended from or closely related to all of the most prominent patrician families of Basel on both his parents' sides. His mother belonged to the noted Burckhardt family, that was considered the most powerful family in the canton of Basel during the 17th and early 18th century. He was a paternal grandson of the theologian Friedrich Seyler and Elisabeth Socin, a member of an Italian-origined noble family, and he was named for his great-grandfather, the Basel judge and envoy to the French court Abel Socin (1632–1695). He was also descended from the Merian and Faesch families. He was a matrilineal descendant of Justina Froben, daughter of the humanist Johann Froben; he thus belonged to the same matriline as Anna Catharina Bischoff. He had a sister, Elisabeth Seiler (1715–1798), married to parish priest Daniel Merian. He was distantly related to Cardinal Joseph Fesch, Napoleon's uncle; they were both descended from the Basel silk merchant, politician and diplomat Johann Rudolf Faesch (died 1659), who was Burgomaster of Basel and led the city's pro-French faction.

Although his parents belonged to families that were highly respected in Basel, Abel Seyler grew up in rather modest material circumstances. His father's congregation was small, and the parish church and rectory were in poor condition. His father also failed in his attempt to have the church restored. As a parish priest, his father did not have a fixed income but presumably lived off payments for church services, gifts and occasional government contributions. It was only when he retired in 1763 that his father received a fixed income, a pension of 600 pounds.

Abel Seyler was married in his first marriage from 1754 to Sophie Elisabeth Andreae (1730–1764), the daughter of the wealthy Hanoverian court pharmacist Leopold Andreae (1686–1730) and Katharina Elisabeth Rosenhagen (died 1752). Her parents were already deceased and her only close relative was her older brother and only sibling, the court pharmacist J.G.R. Andreae, who became a noted Enlightenment natural scientist. The wedding took place in Hanover and Abel and Sophie Elisabeth had two sons and a daughter: Abel Seyler (the Younger), who became court pharmacist in Celle and who was a member of the Illuminati; L.E. Seyler, a prominent Hamburg banker and politician; and Sophie Seyler, who married the Sturm und Drang poet Johann Anton Leisewitz, the author of Julius of Taranto.

After the death of his first wife in 1764, their children were raised in Hanover by their maternal uncle. By several accounts J.G.R. Andreae was a highly erudite, generous and kind man who became a loving father figure to his sister's children; he had no children of his own. The children since had limited or no contact with their father, and all lived more conventional lives than him. They inherited the Andreae pharmacy from their uncle on his death in 1793.

In 1772 Abel Seyler married the actress Friederike Sophie Seyler (formerly married Hensel). They had no children.

The principal founder of biochemistry and molecular biology, Felix Hoppe-Seyler, was an adopted son of his grandson. Seyler was a godfather of Jacob Herzfeld (born 1763), known as the first Jewish stage actor in Germany, when the latter converted to Christianity in 1796.

At the court of Duchess Anna Amalia (1771–1774)

In 1771 the Seyler Company was invited to the ducal court in Weimar by Duchess Anna Amalia, the composer and noted patron of the arts, and Seyler again became the company's principal. They were warmly welcomed by Anna Amalia and her court in October 1771, and were generously paid; the company performed three times a week for select guests at the Weimar ducal court. In 1771 Anna Amalia was a 32-year old widow who reigned as regent on behalf of her young son. The Seyler Company's arrival in Weimar marked the infancy of the cultural era known as the Weimar Classicism, when the Duchess invited many of the most eminent men in Germany to her court in Weimar, including Herder, Goethe and Schiller. The year after Seyler's company arrived in Weimar, the Duchess invited Christoph Martin Wieland to Weimar to educate her two sons. Wieland had just published his modern and ironic mirror-for-princes work, Der goldne Spiegel oder die Könige von Scheschian. Wieland became an important friend and collaborator of both Seyler, and later Goethe.

Adam Shoaff notes,

While in Weimar, the Seyler troupe established a reputation as one of the most formidable companies in Germany, thanks to its composer, Anton Schweitzer (1735–87); their leading soprano, Franziska Koch; [...] and two other talented singers, Josepha and Friedrich Hellmuth. Its production of Schweitzer’s Alceste (1773), with a libretto by Christoph Martin Wieland (1733–1813), marked a significant moment in German opera history: Alceste was the first full-length serious opera in German.

In 1772 he reunited with his love interest Friederike Sophie Hensel, who had stayed at the Vienna Burgtheater for the past year, and they finally married in November 1772 in Oßmannstedt just outside Weimar.