Here's some of what wikipedia has to say:
She was born in 1786 in Saint Petersburg and raised in Pavlovsk.
As a child, she was not considered pretty: her features were disfigured as a result of a pioneering application of the smallpox vaccine. Her grandmother, Catherine II, admired her precocious talent as a pianist but declared that she'd better be born a boy. Her music instructor was Giuseppe Sarti, a composer.
In 1804, she married Carl Friedrich Grand Duke of Saxe-Weimar Eisenach, with whom they stayed in Saint Petersburg for nine months, before departing for Weimar. There she was greeted with a bout of festivities, as described by Christoph Martin Wieland: "The most festive part of all the magnificence of balls, fireworks, promenades, comedies, illuminations was the widespread and genuine joy at the arrival of our new princess". Schiller praised her "talents in music and painting and genuine love of reading", while Goethe hailed her as one of the worthiest women of his time.
After the death of the Grand Duke Carl Friedrich in 1853 she retired from public life.
Her last trip to Russia was to the coronation of her nephew as Alexander II of Russia in 1855.
Maria Pavlovna was interested in arts as well as in sciences. She was a patroness of art, science and social welfare in the poor Grand-Dukedom of Saxe-Weimar-Eisenach. She maintained a lifelong correspondence with Vasily Zhukovsky and it was to her that Schiller dedicated one of his last poems. She attended ten courses at the University of Jena, some delivered by Alexander von Humboldt, and was instrumental in establishing the Falk Institute in Weimar. In her later years, Maria Pavlovna invited Franz Liszt to her court, restoring a measure of artistic excellence previously associated with Weimar. However, her growing deafness prevented her from enjoying the premiere of Lohengrin in Weimar on 28 August 1850.
Most famous were the "Literary Evenings (Literarische Abende)" where scholars from the neighboring Jena University and others from outside the Grand-Dukedom were invited to give lectures on various topics. This circle was a focus in post-classical Weimar.
Several collections of the Jena University benefitted by her patronage, among them the Grandducal Oriental Coin Cabinet founded in 1840 by Johann Gustav Stickel, orientalist at the University.
Maria Pavlovna is buried in Weimar, in a Russian-style chapel by the side of the Goethe-Schiller Mausoleum.
Her son, Karl Alexander, married in 1842, his first cousin, Princess Sophie of the Netherlands, daughter of William II and Anna Pavlovna of Russia, sister of his mother. Her daughter, Marie, married Prince Karl of Prussia, brother of Wilhelm. She also had a first-born son, Paul, who only lived a few months.
This is Marie's husband, Karl Friedrich:
