All the following pieces are copies from various Google articles.
In this book with the title “Marriage of Opposites” Alice Hoffman says in her afterword, that Rachel Pizzarro’s life in her imagined story mirrors the known facts about Rachel as closely as possible.
I reckon it is very rewarding to find out more about the historical background of the book’s characters by googling for some more information. Right in the beginning of Hoffman’s book Rachel says that she rarely did as she was told. Out of all the numerous children that Rachel had, Jacobo Camille, the artist, is by far the most interesting. I would say this novel is extremely well written and that it is based on historical facts makes it all the more interesting.

The story is set on the Island of St. Thomas and in Paris. Charlotte Amalie is the place where Rachel and her family lived. Here are some facts about Charlotte Amalie:

“Charlotte Amalie (/ˈʃɑːrlət əˈmɑːljə/ or /-ˈæməliː/), located on St. Thomas, is the capital and largest city of the U.S. Virgin Islands, founded in 1666 as Taphus (meaning “beer houses” or “beer halls”[1]). In 1691, the town was renamed to Amalienborg (in English Charlotte Amalie) after Charlotte Amalie of Hesse-Kassel (1650–1714), queen consort to King Christian V of Denmark. It has a deep-water harbor that was once a haven for pirates and is now one of the busiest ports of call for cruise ships in the Caribbean, with about 1.5 million cruise ship passengers landing there in 2004. Protected by Hassel Island, the harbor has docking and fueling facilities, machine shops, and shipyards and was a U.S. submarine base until 1966. The town has been inhabited for centuries. When Christopher Columbus came here in 1493, the area was inhabited by Island Caribs and Taíno. It is on the southern shore at the head of Saint Thomas Harbor. In 2010 the city had a population of 18,481,[2][3] which makes it the largest city in the Virgin Islands Archipelago. Hundreds of ferries and yachts pass through town each week, and at times the population more than doubles.
The city is known for its Danish colonial architecture, building structure and history, and a dozen streets and places throughout the city have Danish names. Charlotte Amalie has buildings of historical importance including St. Thomas Synagogue, the second-oldest synagogue in the Western Hemisphere,[4] and the oldest Lutheran church in the Western Hemisphere, the Frederick Lutheran Church. The town has a long history of pirates, especially stories of Bluebeard and Blackbeard (Edward Teach). In the 17th century, the Danes built both Blackbeard’s Castle and Bluebeard’s Castle attributed to the pirates. Blackbeard’s Castle is a U.S. National Historic Landmark. Another tourist attraction is Fort Christian, the oldest standing structure in the Virgin Islands Archipelago. A copy of the Liberty Bell is in Emancipation Park, which is a tourist attraction.

The city was named Charlotte Amalie in honor of Charlotte Amalie of Hesse-Kassel in 1691”

I also found the following about THE DANISH WEST INDIES:

“The Danish West Indies (Danish: Dansk Vestindien) or Danish Antilles was a Danish colony in the Caribbean, consisting of the islands of Saint Thomas with 43 square miles (110 km2); Saint John with 42 square miles (110 km2); and Saint Croix with 100 square miles (260 km2). The Danish West India Guinea Company annexed the uninhabited island of Saint Thomas in 1672 and St. John in 1675. In 1733, Saint Croix was purchased from the French West India Company. When the Company went bankrupt in 1755, the King of Denmark-Norway assumed direct control of the three islands. The Danish West Indies was occupied by Britain in 1802–1803 and 1807–1815, during the Napoleonic Wars.
The intention of Danish colonization in the West Indies was to exploit the profitable triangular trade, involving the exportation of firearms and other manufactured goods to Africa in exchange for slaves who were then transported to the Caribbean to staff the sugar plantations. The final stage of the triangle was the exportation of cargo of sugar and rum to Denmark. The economy of the Danish West Indies was dependent on slavery. After a rebellion, slavery was officially abolished in 1848, leading to the near economic collapse of the plantations.
In 1852, the sale of the increasingly unprofitable colony was first debated in the Danish parliament. Denmark tried several times to sell or exchange the Danish West Indies in the late 19th and early 19th century, to the United States and the German Empire respectively. The islands were eventually sold for 25 million dollars to the United States, which took over the administration on 31 March 1917, renaming the islands the United States Virgin Islands.”

The Synagogue on the Island of Saint Thomas is mentioned frequently in Hoffman’s novel. Here is some more background about this synagogue:

“Saint Thomas Synagogue was built in 1833, and is the second-oldest synagogue on United States soil (after the 1763 Touro Synagogue in Newport, Rhode Island). It also has the longest history of continuous use by a Jewish congregation in the nation. It was built for a congregation founded in 1796 by Sephardic Jews who had come to the Caribbean Basin to finance trade between Europe and the New World.[1]
Features[edit]

The synagogue as a number of distinctive and unique features. Most of the wooden features including the benches, the ark and the bimah are made from mahogany. The menorah dates back to the 11th century and is Spanish in origin. The chandeliers are European and are presumed Dutch. There are four pillars inside representing Sarah, Rachel, Rebecca and Leah, the four matriarchs of the Jewish people. But by far the most unusual feature of the synagogue is the sand floor. There are two theories behind this unusual occurrence. One is to represent the Israelite journey through the desert. Another theory is that it represents the Conversos who were forced to convert to Catholicism. Many continued to observe Judaism, so they usually met in their cellars and would use sand to muffle their prayers.
The congregation is affiliated with the Reform Jewish movement and the rabbi is a graduate of Hebrew Union College.

Here now a synopsis written I think by Tom Morrison:
ALICE HOFFMAN
“The Marriage of Opposites”