Ever heard of Aristotle? You remember him from school right? Avicenna (980-1037) and Averroes (1128-1190) built on his work in Astronomy. Christians saved his work from the Dark ages by Probus of Antioch in the 5th century who introduced Aristotle to the Arabic world along with Christian Huneyn ibn Ishaw (809-973) who not only translated Aristotle by Galen, Plano and Hippocrates into Syriac which his son then traslated into Arabic.
The Jacobite Christian Yahya ibn Adi (893-974) also translated the works of philosophy into Arabic.
Andreas Vesalius (1514-1564) paved the way for modern medical advances by publishing the first accurate descritption of human organs De Humani Corporis Fabrica. It was him and not the Muslim world because his faith did not preclude autopsies something forbidden in Islam.
As far as Algebra, Abu Ja'far Muhhamad ibn Musa al-Khwarizmi (780-850) considered one of the greatest mathmatitions in history and where the term "algorithm" comes from gathered his material including the zero from pre Islamic India hundreds of years earlier.
So yes there were great accomplishments but they were born from other people's work from Europe and India.