Anna Catharina Lowies

Hypothesis: Jan Lowies, SV/PROG and Johannes Lodewijk Meijer are one and the same person and Anna Catharina Lowies and Anna Catharina Meyer are one and the same person as well:
Jan Lowies is mentioned as witness at the baptism of Francois Gerhardus Peffer, son of Johannes Lodewijk (Lodewijk) Peffer and Catharina Wilhelmina Peffer, on 21 May 1817 in Graaff-Reinet. I suppose this means that Jan Lowies already was a friend of the Peffer family at that time. Both Lodewijk Peffer and his wife Catharina Toornheim were coloureds that descended from German immigrants; Lodewijks Peffer was a German immigrant that married a lady from the Kaap and Catharina Peffer was a granddaughter of a German immigrant, her maternal grandmother and her mother also being local ladies from the Kaap.
If Jan Lowies and Johannes Lodewijk Meijer were the same person, than Jan Lowies was a German immigrant himself. Which might explain why an apparantly total stranger ends up as a witness at a baptism: they belonged to the same German immigrant community in early 19th century Graaff-Reinet.
Somewhere around 1817 Lodewijk Peffer's sister Anna Catharina Meyer became a young widow, with three small children to take care off. In 1818 she remarried, with Johannes Lodewijk Meijer. My assumption is that the groom, who was a family friend of the bride's brother, agreed to marry the young widow and take care of her family. Although he called himself Jan Lowies (the Dutch short name for German Johann Ludwig) at the time, at his marriage his formal surname Meijer was entered into the records. Same happened at the birth of their first son Johann Jurgen, named after his maternal grandfather.
But when the second child was baptised in 1824, everybody had forgotton about the surname Meijer again and the father was recorded as Jan Lowies.
This perfectly explains why their is a couple Johannes Lodewijk Meijer and Anna Catharina Peffer recorded in Graaff-Reinet from 1818 to 1821, that vanishes into thin air after the baptism of their first son. And why there is a couple Jan Lowies and Anna Catharina Peffer from 1824 onwards in the same city that does not appear in any record before that time.
The last child from this marriage was born in 1833, when the mother was around 40 years old, a very credible age for a woman that gives birth to her last of at least 10 children.

There is no conclusive evidence yet for this hypothesis, but there is a partial DNA match between 6th generation descendants of Anna Catharina Lowies and 7th generation descendants of Johannes Lodewijk (Lodewijk) Peffer, that could be explained if they were brother and sister. The ancestry tables of descendants in both lines still contain a lot of unknown ancestors, so there could be other yet unknown ways in which they are related, but at present this seems to be the best explanation for the partial DNA match.
(Willem Nabuurs, 7 november 2018)

Witnesses at the baptisms of the children of Jan Lowies and Anna Catharina Peffer:
1. Johanna Catharina, born 13 May 1824, baptized Graaff-Reinet op 't dorp (Nederduitsch Gereformeerde gemeente van Graaff-Reinet), 12 september 1824: William Radele and Maria Pretorius
2. Sara Christina, born 25 October 1825, baptized Toberberg (Nederduitsch Gereformeerde gemeente van Graaff-Reinet), 12 March 1826: Gerret Petrus Coetze, Martha Jacomina Pienaar, Johannes Jacobus Grobler en Cornelia Pienaar
3. John, born 21 May 1827, baptized Torenberg (Nederduitsch Gereformeerde gemeente van Graaff-Reinet), 9 March 1828: Josef Mathijsen, Willem Lodewyk Peylman and Cicilia Visagie
4. Lodewyk Jacobus, born 17 August 1828, baptized Renosterberg (Nederduitsch Gereformeerde gemeente van Colesberg), 12 October 1828: Gideon du Toit and Emily Geel
5. Anna Catharina, born 23 May 1830, baptized Renosterberg (Nederduitsch Gereformeerde gemeente van Colesberg), 15 May 1831: Schalk Willem Burger, Adriaan Jacobus van Wyk and Maria Burger
6. Margaritha Elisabeth, born 9 December 1833, baptized Renosterberg (Nederduitsch Gereformeerde gemeente van Colesberg), 8 December 1834: Gabriel Ernst Yselle and Margaritha Elisabeth Stiggeling