By Marc Jones LONDON (Reuters) – Russia’s first major international debt default in over a century, which Washington said became a fact on Monday, follows months of co-ordinated Western sanctions that left Moscow with cash but no access to the international financial network. Below is a summary of the key moments that have led up to this point. THE “BIG PACKAGE” At around 11.30 p.m. (2230 GMT) on Feb. 25, the day after Russian troops entered Ukraine, European Union’s experts in Brussels said a set of sanctions they had worked on for days, or the “Big Package” as they called it, was ready. Just…