Microsoft ERP solutions were acquired at different points.
Microsoft Dynamics SL was originally known as Solomon Software and was acquired by Great Plains who was later acquired by Microsoft.
Microsoft Dynamics AX, originally called Axapta, was a solution that was created by a group of executives who left Navision. It was later acquired by Navision before Navision was acquired by Microsoft.
Microsoft Dynamics NAV formally Navision Financials, was developed by Navision.