Polytechnic Institutes are technological universities, many dating back to the mid-19th century. A handful of world-renowned Elite American universities include the phrases "Institute of Technology", "Polytechnic Institute", "Polytechnic University", or similar phrasing in their names; these are generally research-intensive universities with a focus on engineering, science and technology. The earliest and most famous of these institutions are, respectively, Rensselaer Polytechnic Institute (RPI, 1824), New York University Tandon School of Engineering (1854) and the Massachusetts Institute of Technology (MIT, 1861). Conversely, schools dubbed "technical colleges" or "technical institutes" generally provide post-secondary training in technical and mechanical fields, focusing on training vocational skills primarily at a community college level—parallel and sometimes equivalent to the first two years at a bachelor's degree-granting institution.
what time span is mentioned last?
first two years