Ignaz Schuppanzigh was a famous violinist in Beethoven's time.
He was born in 1776 and died in 1830, a few years later than Beethoven. They probably first met at the end of the 18th century at one of his informal quartet concerts in Prince Lichnowsky's apartments (one of Beethoven patrons).
What is interesting (for this website) about Schuppanzigh, is that he started his career as a viola player and then switched to the violin, alas, something that almost all musicians used to do if they wanted to be leaders.
Around 1804 Schuppanzigh presented the first series of public quartet concerts in Vienna, soon abandoned. Before that, quartets and other chamber music compositions were not performed, as they are today, in public concerts but they were actually intended and used for private performances, in the houses of wealthy people.
In 1808 Count Razumovsky, another of Beetheven's supporters to whom he dedicated his op.59 quartets, asked Schuppanzigh to create the finest quartet in Europe. Surely, having played the viola, his first hand knowledge of the instrument also contributed to his role as a quartet leader and to the quality of the performances.
From 1816 to 1823 he lived in Russia, in St Petersburg, where he promoted Beethoven's music. Back in Vienna he continued his activity as a quartet player.
Beethoven used to tease him incessantly and called him Falstaff because he (Schuppanzigh) was quite fat. Nevertheless, Beethoven respected Schuppanzigh as a musician and there are testimonies of Schuppanzigh's suggestions used by Beethoven. Schuppanzigh's quartet was responsible for the premiere of several Beethoven's quartets. Also in 1824 he led the orchestra and helped to organize the concert for the first performance of the Ninth Symphony and parts of the Missa solemnis.
Ignaz Schuppanzigh, together with other important musicians, was one of the torch-bearers at Beethoven's funeral.
Nowadays Schuppanzigh is remembered only in relation to Beethoven, still another important fact about him is that he was one of the first musicians to make his living and reputation mainly as a quartet player.