The Free On-line Dictionary of Computing (30 December 2018):

Intel 8048
8048

    The microcontroller used in IBM PC keyboards.
   The 8048 was inspired by, and similar to, the Fairchild F8
   microprocessor but, being a microcontroller, was designed for
   low cost and small size.  The 8048 has a modified Harvard
   architecture, with program ROM on chip and 64 to 256 bytes
   of RAM also on chip.  I/O is mapped in its own address
   space.

   Though the 8048 was eventually replaced by the very popular
   but bizarre Intel 8051 and Intel 8052, even in 2000 it is
   still very popular due to its low cost, wide availability, and
   development tools.

   [Was it really __the_first__ microcontroller?  Are the ROM and
   RAM both on-chip?]

   (2000-06-01)